Inboard Diesel to Outboard 4-Stroke?

[Grateful Dad]

While motoring my 1977 Hunter 27 from my Summer dock site to my Winter hauling and storage site, the old Yanmar YNB-8 pretty much died on me. No power, lots of brown and then white smoke, etc. My mechanic and I did some preliminary work such as changing fuel filters but it ultimately looks like a damaged rings or worse. We will do a compression check after Thanksgiving but it doesn't look good for the old girl. So my thought process is centered upon whether to repair/rebuild the diesel or replace it with an outboard.A little background on the boat and it's usage:The boat was poorly maintained before I bought it in October 2005. (I bought it as a project - and I have not been disapointed...) The engine was never rebuilt or repowered as far as I know but did run fine all summer. There are some soft spots on the deck above the cabin. I have rewired it (AC and DC) and added new cushions, stripped and sealed below the waterline, painted topsides, replaced the cutlass bearing. New sails will be added this winter. I plan to continue working on it until it is comfortable and looks nice. I expect to keep it for about 10 years. I use it primarily for daysailing and coastal cruising.On the plus side for rebuilding the diesel I come up with:Keeps the boat as designed.Handling underpower will be about the same. (The devil you know)No shaft openings to fill.On the plus side for removing the diesel and adding a new 18HP 4-stroke outboard:Less expensive. (~$4K to rebuild vs. ~$3K for outboard, controls, brackets, installation.)I can take it with me if I decide to change boats.Handling underpower may be improved. (Less prop walk to port in reverse?)Everything (engine-wise) will be new.More power - the 8HP diesel was almost under powered.Quieter - certainly in the cabin.More storage space in the cabin.So finally my questions:1. Has anyone had experience doing this? If so, what were the gotchas, pluses, and minuses?2. Will the handling be much different?3. Is there a brand of outboard that is better or one to avoid?4. Any other suggestions?

 

[Rob19574]

Rebuild

I don't have the time to go into great detail on this but my thoughts are: Rebuild what you have.- Not sure where you could get an 18 HP w/ controls for 3k...sounds low.- There will be a number of handling issues with an outboard mounted moter vs. the inboard.- Alternator is goig to be different.- Try rebuilding her yourself over the winter.....its not a complicated motor. I did a YSM12 and its runs as good as new!

 

[Ross]

You can have an automotive machine shop

clean the block and bore the cylinder if it needs it. They can also supply most if not all of the parts you will need. I had a four cylinder Volvo gas turbo engine for my wagon completely rebuilt and reinstalled for about 6k$. You can hoist the engine out of the boat with your mast, boom, running rigging and some helping hands. The engine probably doesn't weigh any more than a man. If you must buy tools get the best and then you will have them.

 

[Don]

another rebuild vote

Parts are readily available and it will likely be lots more dependable than ANY outboard plus you don't have the gasoline issues. You also get better weight distribution, better charging system and increased value of the boat as collateral pluses and an outboard hanging off the back detracts from it's appearance too. It would also be a nice winter project and probably cheaper as wellDon

 

[Arthur Stock]

Rebuild II

I back up Rob 100%. An inboard engine with alternator will keep you charged better than an outboard with altenator. What output do you need to charge your battery (ies)? Are you quibbling over $1 k on a 10 year investment? Compare potential resale values. My guess is inboard will get you $500-800 more on resale. While you are at it, pull the fuel tank and clean it out. If it is fiberglass, consider replacing it with a metal tank. Ethanol has been giving marine gasoline engines grief this year and diesel will have a new additive next year. Get the junk out now.

 

[KennyH]

It has been my experience over many years

It has been my experience that a rebuild is never as good as factory fresh. It makes sense if the engine is a collectors items like my 1960 TR3 which has been rebuilt. With a boat engine a complete factory fresh replacement is the way to go. Lots of manufactures have engines designed to replace yours with little modification. You get everything new and fresh and your engine compartment looks like a new boat if you clean it up after the old one comes out. It also adds value to your investment that you have a "new" engine. You will spend 3/4 of new for a rebuild and not have anywhere near the dependability of a new engine. This is the way to go in my humble opinion.You would not be happy with an outboard offshore and you mentioned coastal cruising.

 

[Benny]

Consider repower to a Yanmar 1GM10

It will cost you about what a rebuild would. The problems with an outboard are a few;1) weight: have to install a motor mount rated for the weight of the outboard. The transom will have to be adequately reinforced with a back plate.2) The propeller will not be centered with the rudder unles you place the engine right in the middle blocking your swim ladder. This will cause it to back up even worst than when you had the diesel.3) Have to run new control and fuel lines to the engine. A gas tank needs to be adapted. Remember gas fumes are explosive.4) In rough seas the prop will have a tendency to leave the water.5) Maintenance will have to be conducted hanging of the transom or from a dingui.6) Their alternator is very weak compared to the diesel's.7) Fuel consumption, even with a 4 stroke, will approximately double reducing range under power.8) Hanging an outboard from a boat that was originally designed for an inboard generally detracts from its value. I would stick with a diesel and would compare cost of a rebuild versus the price of a new one. Over a ten year period the difference in cost between either choice or an outboard may be a couple of hundred dollars a year if the outboard lasts that long. The ease of operation of the diesel will be more than worth the extra expense on the long run.

 

[Jeff]

Go with the Outboard!!!

I had a 1984 Starwind 27 with a 10hp outboard thatdid great. I now have a 1984 Hunter 31 with Yanmarinboard and I wish I had an outboard! My outboard wasa 2 stroke Johnson 9.9hp longshaft. I have had thatengine since 1993 and have only changed the plugsa couple of times and it starts right up every timeIt has electric start and alternator. The outboard was much easier:Can spin the boat on a dime in forward or reverse.No prop walk! No leaky shaft packing or alignment problemsNo stinky dieselNo messy oil changes in the bildgeNo dragging a prop to slow you down under sailNo worry about contaminated diesel and multiple filtersNo bleeding the air out of the fuel systemProp is BEHIND the rudder, so no rudder prop wash in forwadMore space onboardNo through hull valve to open and close all the timeNo noise inside and terrible vibrationsEasy to winterize and use in winterNo exaust hoses and muffler inside the boatNo worries about what rpm to run at and "sweet spots"Easy to clear the prop if it gets fouledEasier to work on and remove if neededEasy to switch enginesCheaper to repairLess weight than Dieseldon't have to worry about growth on propOutboard is cheaper then diesel(replacement on my Yanmar 18hp was 8K!)No hot diesel engine in the boat an a hot summer day!Gasoline easier to find and cheaper Disadvantages of Outboards:Can cavitate in high wavesStern doesn't look as niceHarder to put on stern ladderLess fuel economyHave to tilt up and down to use (but an electric tilt would be cool!)Weight over the back of the sternGas more dangerours (put fuel tankin outside locker etc.)Life was so much easier with an outboard.I have had to do more work on my Yanmar dieselwith only 50 hours on it in the first two months than over 20 years on the outboard. You don'tneed a diesel in a 27 footer unless you are doinga lot of motoring in heavy seas.I run my engine as little as possible for shortperiods... which of course is bad for a diesel engine.

 

[Bad Obsession]

Rebuild or repower with diesel

A lot of people hit the nail on the head. With the diesel you keep the re-sale value. Added to that, if you are keeping it for a while, a diesel engine will last longer than an outboard. One thing not mentioned, it is a hell of a lot harder to steal an inboard than an outboard.Rebuild!

 

[Jeff]

Outboard brand

I have had great luck with Johnson and Nieson engines. Had a friend with a1965 Honda four stroke that did greattoo. Never had any problems with it.Bad luck with Chryslers!To work on an outboard when the boatis in the water, just back it intoa slip and sit on the dock No pullinghalf your boat apart and standingon your head to work on your engine.Really easy to work on them when yourboat is out of the water! Isn't the hunter 27 rudder on a shaftthrough the back of the cockpit? Do youhave wheel steering? I single handedmy 27 all the time and it was much easierto handle under power than the diesel.I had mine so that I could turn the outoboardif I got in a jam, so I was never worredabout any situation or wind condition.I could litteraly spin the boat in circleswithin it's own length. In bad crosswindsor strong wind conditions, I can't take my hunter out solo with the diesel. I never had to worry about docking on thestarboard side with a port prop walk!

 

[Fred]

I've had both inboard diesels and ourboards

I've has several of both inboard diesels and outboards on 25 to 27 foot boats. This is a constant topic on the Catalina 27 forum. You are in the size and weight range where an outboard or a diesel will work well for you. If it were a 30 footer I'd say an inboard is better.A new four stroke outboard will push the boat as well as a diesel for almost the same fuel consumption. I don't think you need 18 hp. Look into a Yanmar 4 stroke long shaft high thrust outboard. It has a bigger prop and a reduction gear in the bottom gearcase. Great motor!The diesel will keep the prop in the water in rough weather, and you will have more battery charging ability. If you use a lot of lights and anything like electric refrigeration, you need the inboard. If it's just lights, converting to LED bulbs may be enough. Solar panels help, too.A dead battery is not such a big deal, since you can pull start the motor. That's a big advantage.For me, the big advantage of the OB is no diesel or gas smell in the boat, and a truly large storage space where the engine was.Listen to all the advice, then go with your gut feeling.

 

[Jeff]

Resale value??

What do you think a 1977 Hunter 27 is going to be worth in another 10 years? The moneyyou spend on a new diesel and transmission etc.is going to be a lot more than you are goingto get back in resale value! I would be moreworried about not getting the return in theinvestment. As he said, he can take the outboardwith him if needed and there is nothing to saythat he can't still keep the diesel and rebuildit at his leisure as time and money permits.It's no big deal to drill four holes in a transumand back it up with some lumber for a mount.And it's just as easy to unbolt that mount andfill the holes. I know because I've done it!Hanging an outboard on the stern could evenbe a tempory solution until he gets a biggernew diesel. I guess a lot depends on how much he uses hisengine. I only use mine when there is no windto get back to the marina and to get in and outof the slip. I have had to use it once to cross the bottom part of Lk. Michigan in the fogat night with no wind and in two storms when thewind was too strong for sails I had.I think as others here do that a fresh factorydiesel would be better than a rebuilt. Sounds likea bigger engine is desired anyway, so a rebuildwould be out in the case of keeping the diesel.Is the diesel in your Hunter 27 a single cylinder?Years and years ago, I chartered a Hunter 27 with aone cylinder yanmar and it shook the stuffing out of that boat!

 

[Moody Buccaneer]

More ...

"Resale value?? What do you think a 1977 Hunter 27 is going to be worth in another 10 years?"More with a working inboard than with a non-factory outboard butchered onto the transom, much more than the boat with no engine at all."It's no big deal to drill four holes in a transumand back it up with some lumber for a mount.And it's just as easy to unbolt that mount andfill the holes. I know because I've done it!"Remind me not to buy a boat from you.

 

[Jeff]

That's not nice and not productive

Who said anything about butchering? You don'tthink that an outboard can be put on a boatcorrectly? The work I do on boats is betterthan factory! Besides, what do you thinkis still "factory" on a 1977 model hunter that'sstill any good? Factory on a Hunter wasn'tthat good to begin with! I bought a 1984 Hunter31, everything was "factory"and all had to be replaced. Everything I replaced on the boat is better than factory.And yes I did sell the boat that I took the outboardoff the back and filled the holes and I see thatperson and sail on that boat all the time and it'sperfect and you can't tell there ever was an outboardon the back. It was not "botched" in the least!I would not sell a boat to you anyway. You are insultingsomeone that you don't even know and have never seen thework I do. I am not opposed to spending more on a sailboat than it'sworth, but in that case you are not looking at it asan investment and resale value takes a backseat to howyou want the boat to be for the next 10 years.If you spend 5K on a cheap fixer up boat and thenspend 6K on a new diesel, I don't care what you say,resale value is out the window especially when you aretalking about all new sails, painting the decks etc...Especially when you are talking Hunter. If it was a Tarten or Island Packet etc. you would have somethingworth spending the bucks on and get better resale.I think the advantage of a cheap boat that needs everythingreplaced is that you can make it how you want it andhave the pride and satisfaction that you did it yourself. My priority would be on sails and rigging. An outboardwould be much cheaper and do just fine, unless you prefermotoring to sailing. And... I never suggested that he should sell the boatwith no engine. I guess you missed the part where I suggested that he keep the inboard and rebuild it.I was simply suggesting that if he did put an outboardon the back, there's nothing to say that he couldn'ttake it back off. Nothing wrong with keeping your optionsopen. I was just saying that he will probably get better resale value with the inboard, but that the addedresale value won't be enough to make up for the bigbucks spent on a new diesel with all the trimmings.He says that 8hp isn't enough for his situation, sorebuild is out of the question. Parts exceed valueno matter how you look at it. So, forget about resalevalue, make the boat how you want it within the budgetyou have and enjoy.

 

[Scott]

I would have said to replace the old ...

with a new diesel that has more power. But Jeff's arguments are the most convincing. Dad, it's up to you ...Jeff, we have an '84 Starwind 27 with a inboard diesel (Yanmar 1GM). The inboard went through a re-build a few years ago (by the p.o.) We like the boat quite a bit. What became of yours?

 

[Randy Burns]

Good question

I recently repowered my Hunter 27 with a Yanmar YM15. I bought the boat cheap with a bad motor. I previously had a 25 with a Honda 9.9 on the back. There were a few times I felt a little insecure with the depth of the Honda prop in rough seas, and I always wondered about trying to fix something hanging over the back - but it was reliable and between the rudder and the outboard I could turn on a dime. Im a do-it youselfer and I put about $6000 into the new inboard and am happy with it. The Honda was about 3000 a few years back. I still have the YSB 8, and may have rebuilt it except most everyone seemed to think it was underpowered. The resale value with an inboard will be greater than the outboard, but I don't expect to ever get back what I've put into her.

 

[Jeff]

Scott

I'm selling my Starwind 27 only because I haveto pay for the 1984 Hunter 31 that I bought.The Starwind is a great boat and sails fantastic!Mine has wheel steering and an outboard. Afterdealing with all the stuff you have to go throughwith a diesel as I mentioned earlier, I preferthe outboard. We are on small inland lakes and neverencounter real high seas and I run the engine verylittle as I like to be able to sail in all situations. We sail in the local sailing clubs as much as possible. I always said that starwind would be perfect for us ifit was just a little bigger. For a couple of people, it'sperfect and it's a great boat to singlehand as the genoa winches are far enough back. An owner before usput some nice Lewmar 40 2 speed self tailing winches onthat are great! Wish I could put them on the new boat!Our Hunter 31 has a deep fin keel like the Starwind andperforms very well. Kinda reminds me of a larger Starwindexcept the Hunter is not as well made. The great thingabout the Starwind also is that it's a very unique boatand it's the only one on these lakes. I always had peopletelling me what a great looking boat it was and askingme what it is. Now that I have this Hunter 31, there are5 others just like it in the marina. Who knows, if thisHunter keeps giving me problems, maybe I'll sell it andkeep the Starwind. I have to try to align the propshaftand figure out why the diesel is running so rough, so no sailing for me again this weekend! This Yanmar only has 50 hours on it and it doesn't run nearly as niceas my 1993 outboard on the Starwind. I sailed my Starwind for 6 years and it's the best sailingboat I've sailed so far. How long have you had yoursScott? The ice box in our Starwind was converted with an AC/DC refrigeration unit and it was wonderful. Hard to live without it on the Hunter. What upgrades are on yours?

 

[Moody Buccaneer]

Apology to Jeff

My remarks were uncalled for and undeserved. I'm sorry.I respectfully disagree with putting an OB on any boat that was designed for an inboard.I've never heard a marine professional recommend it as an option. I've never seen a boat made better by such a swap.

 

[Jeff]

Reply to Moody

The Hunter 27 of that year was "designed" for either inboard or outboard. I have a Starwind27 that came with EITHER an inboard or an outboard.The only difference between my Starwind and aninboard Starwind is the bracket on the stern andminus two holes BELOW the water line. My Starwindis faster than the inboard models and easier to maintain/winterize etc. The outboard weighs less thanhalf of the inboard and I don't have all the headachesof a diesel. Lots of boats between 25 and 28 feet come with EITHER inboard or outboard such as the Catalina25&27, Chrysler 26, Cal 25,27 & 29, Hunter 25,26.5,27C&C 25 & 27, Freedom 25,Islander 27, Morgan 27, Newport 27Oday 25&27,Santana 27 etc. My boat came with either a tilleror wheel. Originally it did have a tiller and someone put awheel in it and you would never know the difference exceptthe original tiller was lying in the V birth. With your logic, theboat is no good with the wheel because it was designed withthe tiller and so the boat should be worth less. I happenedto buy it because it did have a wheel and an outboard. No I haven't heard a "Marine Professional" recomendswitching from inboard to outboard either. But thenI haven't asked one yet. I know three of them and Iwill ask. I would imagine that generally, a marine mechanic would rather put a dieselback in because he would make much more money and it wouldbe a straight R&R job. I cantell you that there is a Hunter 26 on my dock that hadan electric inboard engine in it and it never worked right, so Hunter installed an outboard on the sternand it's worked great ever since. I have personally mountedan outboad on the stern of a boat that had an engine well in thecockpit that was miserable. The outboard on the stern was muchbetter and could be tilted up out of the water. As far as resale value, I agreed with you that you would get more out of it with a good diesel. It's not going to matter though because of how much more the diesel is going to cost vs. the outboard and he can probably install the outboard himself and save even more.Since his boat is in bad shape and needs lots of work,he should have paid about 5K or hopefully less. The best77 Hunter 27 that I could find was $7900 in really nice shape with newer sails, good engine and upgrades.A new bigger diesel is going to cost at least 6K andnew sails about 3K or 2K if he finds a really good deal. So he is going to spend at least 8K on a boatthat he paid about 5K for. So he'll have at leasta 13K in it just to START not including paintingthe decks, running rigging etc etc... In another10 years, it's going to need new sails again, decksrepainted etc. and the diesel will be 10 years oldand it's still going to be a HUNTER. Lets just say that he gets 2K more for it in 10 years becauseit has a diesel instead of an outboard, he paidat least 2k more for the diesel to begin with. Whatis the boat going to be worth in 10 years? It's atotal loss, but you can't put a price on having funsailing for all those years, so you might as wellmake the boat how you want it regardless of resale.And, let's face it, this boat is not headed for bluewaters.So, I think it comes back down to personal preference.I think, in a 27 foot boat, the less weight and complication,the better. And on a 27 footer, every inch of extra space insideis worth a great deal. Once you hit 30ft, you have a diesel inboard.So, if you are planning on getting a bigger boat, you mightwant a diesel in the 27 footer so that you learn and are prepairedfor that. I prefer to go sailing and anything that takestime away from that or makes it harder is not my idea of fun.What boat are you sailing ?

 

[Moody Buccaneer]

You are quite correct.

There was a period of time that both inboard and outboard options were offered on many boats in the 25-30 foot range.If you have one of those boats, changing from inboard to outboard would not be changing the design. However, on many of those boats other items, fixtures, etc are in different positions so that the CG is close to the same with either power option. If this is not done the boat will not sit on her lines properly. Depending on where the inboard was mounted and how heavy it is, the change to an outboard may not move the CG enough to upset the boat.Another thing to remember is that those boats were designed with a 9.9-15 HP 2-stroke engine that weighs about 90 pounds, not the 125+ pounds that today's 4-stroke engines weigh.Catalina 27's are a prime example. The factory OB mount placed the OB in the space that is normally the aft cockpit locker. Several people have found out that the powerhead of the new 4-strokes is too large to be used in the standard mounting.Obviously changing form one designed option to another should not compromise the boat. Some boats are better with one set of options than others. The J-29 came in 4 factory configurations. IB with masthead rig, IB with fractional rig, and OB versions of both. The OB versions are faster and have lower ratings than the IB boats.My first boat was an Excalibur with the OB in a well. It was the right setup for that boat. When sailing I stowed the OB in the head and plugged the well ... but I was so much younger then. I've never liked sailboats with the OB on the transom, the racer in me just can't stand to have the weight hanging out back there.My current boat is a Catalina 30 (1975, Hull #10) with the original Atomic 4 and tiller steering. It's been out of the water for 13 months now, getting the hull dry, the keel bolts replaced, and a paint job. The A-4 will go back in the boat, compression is still 100-105 in all cylinders (and I hate the smell of diesel). And yes I'll have spent more than twice what the boat is worth before I'm done. :|I think you are a bit hard on marine mechanics. People that recommend the option that makes them the most money only last as long as they can find new customer's (the old one's don't come back). I'm a rigger, I base my recommendations on what I think will best serve my customer's needs, even if it means selling a low profit item or service. We refuse to sell things we know won't work or would reflect badly on the shop. People can go to West Marine for that. Once again I'm sorry I snapped at you. No excuse for that here.