Reviving old engine

[dLj]

So I'm just going to put this out there. Everybody here has given me so much really good advice and ideas, maybe this would also be a good discussion.

So - I bought an old Cherubini Hunter 30, 1977 vintage. It's been sitting on the hard for a long time. Nobody really knows for sure how long. The last sticker on the boat is from 2002, so potentially it may have been sitting where I found it for the past 15 years. So I'm going through the process of restoring this boat. (God only knows why at this stage in my life I decided to take on this project, but that's now a done deal. Well - OK - it really is a beautiful boat...or at least will be...)

The engine is the Yanmar YSB12 and from all external appearances appears to be in decent shape. It spins by hand very easily, has compression, decompression lever works fine, basically appears externally to be in quite decent shape. However, it's been sitting for potentially 15 years without ever being touched.

So what suggestions do folk have to get this engine back into service? I figure I need to clean the fuel tank, flush the fuel lines, change fuel filters, change engine and transmission oils. Then see if it starts. Are there any other suggestions? Cautions? Other things that should be done? I'd like to hear what folk have to say.

Thanks,

dj

 

[jssailem]

Sounds like a great start. How about looking for a manual? My Perkins manual has a descriptive chapter on recommissioning the engine. It is what I used to bring my engine back from a 2 year rest.

 

[kloudie1]

You have a great list.. The only thing I'd add is to check the valve clearance and set it correctly.. It should start after your list is complete and the air is bled out.

 

[dLj]

Yes, I've looked extensively for a manual. Have found several and downloaded them.One is a service manual with operations manual all in one - close to 250 pages long. It has a decent section in it on how to start the engine for the first time. Nothing on extended storage. Haven't seen that in any of the others either.

dj

 

[dLj]

Valve clearance is easy enough to do - nice suggestion - hadn't thought of that....

dj

 

[jssailem]

Ok. I'll see what I can find on my Perkins and forward to you.

 

[dLj]

That would be awesome! Thanks!

dj

 

[smokey73]

I wonder if it might be a good idea to remove the injectors and squirt a little oil or "Marvel's Oil" or some other similar product into the cylinders then roll it a few times either by hand or with the starter to coat moving parts before just "starting it up". Seems that what my Dad did (and he was a great mechanic) anytime we started up an old engine after a few years of sitting idle. If you're in the water just be careful not to crank it too long and water lock the engine from the raw water injection into the exhaust mixer. Obviously, if you are not in the water you'll need to provide an external cooling water source to the exhaust.

 

[litrenta1]

after that much time you probably want to check or change the impeller since it has been sitting dry the rubber may be dry/cracked. Same for the motor mounts make sure rubber is good since as a 1 cylinder engine vibration can get out of hand.

 

[Ralph Johnstone]

Are there any other suggestions?

Replace V belts.

 

[Jalepeno]

I have the bit newer YSM12. I'd do all of the above except for the oil into the cylinder part, plus clean the lube oil strainer and turn it over with the hand crank while holding the decompression lever open. The hand crank will give you a good feel for the compression. Maybe squirt a bit of WD40 into the air silencer (there is no air filter) before using the electric starter. She should start if you have have got rid of the air in the lines. IF she dosen't or runs poorly, take the injector out and have it cleaned/rebuilt at any competent diesel truck shop (~$200 max), Remember you need to put the regulator (it is not a throttle) around the mid speed position for starting. Idle speed should be about 900 rpm, cruising speed is about 2500-2600 rpm and max speed is about 3000 rpm. Avoid the 1700-1800 resonant speed zone. Good luck.

 

[Bill Roosa]

Don't worry about the valve clearance. That will not change with no engine hours. set the decompression lever and crank the engine (always less than 15 seconds or the starter motor overheats) several times till the oil pressure buzzer goes off for a few seconds after you stop cranking. Start the engine.
You might want to change the oil and anti but the engine should not require special attention to get it started.

 

[dLj]

Ok - I'll report back in a couple weeks or so.. I'm only able to get up to the boat weekends. So time is limited... I hope it only takes a couple weekends... But... it is working on a boat...

dj

 

[Captn Scotty]

If the fuel lines are that old check for cracks and pliability, they could allow air into the system if everythings gone hard?

 

[cjm1]

Pull water discharge hose and let water flow to the bilge rather than the exhaust system. With compression release crank engine with full throttle which will spray diesel into the cylinders and lube at same time. I do this every fall and spring but allow starter to cool after 15 seconds and maybe repeat.

 

[Alan Gomes]

Pull water discharge hose and let water flow to the bilge rather than the exhaust system.

Why?

 

[Davidasailor26]

Why?

Otherwise cranking the engine will eventually back coolant water up the exhaust and into the cylinders.

 

[jeepbluetj]

Or you could shut off the thru hull anyway. The impeller likely needs to be replaced - start the thing with no water to see if it starts.

 

[Alan Gomes]

Otherwise cranking the engine will eventually back coolant water up the exhaust and into the cylinders.

I wondered if that might be what he had in mind, but he did not say anything about continually cranking a non-starting engine--hence my question. But that assumes the engine is going to be hard to start and require lots of cranking. If the engine does fire up the water is needed to cool the exhaust, so you would not want to run it that way.
A better solution would be to open the drain plug at the bottom of the lift muffler (which many if not most lift mufflers have) and let the water drain out of the muffler and into the bilge from there. That way, if it does fire right up there will be cooling water going to the exhaust to keep it from overheating.

 

[Davidasailor26]

I wondered if that might be what he had in mind, but he did not say anything about continually cranking a non-starting engine--hence my question. But that assumes the engine is going to be hard to start and require lots of cranking. If the engine does fire up the water is needed to cool the exhaust, so you would not want to run it that way.
A better solution would be to open the drain plug at the bottom of the lift muffler (which many if not most lift mufflers have) and let the water drain out of the muffler and into the bilge from there. That way, if it does fire right up there will be cooling water going to the exhaust to keep it from overheating.

He said to release the compression lever, so it won't start anyway. In any case your method of opening the muffler drain seems like it might work too.