Auxiliary Outboard Engines

finding41 · Nov 5, 2012

This is the first I have heard of running a 2 stroke dry to help with starting etc. I have 5, 2 stroke engines and haven't had a problem. The idea that the 2 stroke oil coats the carb is something I haven't thought about before. This was the first year I found out about ethanol in gas! so I used ethanol free gas in my OB this year.
But Only for the OB because it wasn't on my mind when I was getting gas for the blower, trimmers, or saws. They have never been a problem other than primer bulbs and fuel lines. The saws and hedge trimmer get used maybe once a year... I just add new fuel and off we go.
So now to the snow blower. Guess what I'm going to use in it.... Yes the left over mixed fuel form the boat. I left fuel in it all summer and expect not to have a problem. Come spring I hope I have mixed fuel left for the lawnmower. Mostly because that means I didn't have to blow much snow.
I have never used any stabilizer in fuel but was thinking it might be a good idea with the out board.

John23883 · Nov 5, 2012

Try new spark plugs!

My 9.9 Nissan/Tohatsu 4-stroke had these problems after the first year and after a few seasons of trying everything, mostly carburetor work, I finally called my son-in-law who said, change the spark plugs. It instantly worked better and has run flawlessly ever since. It turns out one of the spark plugs had a hairline crack at the burn line at the edge of the wire boot. Never saw it!

anchorclanker · Nov 5, 2012

finding41 said:
This was the first year I found out about ethanol in gas! so I used ethanol free gas in my OB this year.
But Only for the OB because it wasn't on my mind when I was getting gas for the blower, trimmers, or saws.

Your situation is different, your fuel doesn't have all the garbage that many areas down here have to deal with. Some area have such strong chemicals in the fuel it will eat through fuel lines in a season if the fuel sits long enough to turn sour

Mark Maulden · Nov 5, 2012

ethanol free gas and don't let it run dry. Use the ethanol sort of stabilizer either with or without ethanol free gas. If you let it run dry, condensation can occur within the system and we all know what water does with any metals over time......

CaptDon01 · Nov 5, 2012

The answer has been mentioned several times.....Seafoam. Except no substitutes! Run a stong dose for a while, even as heavy as a full can in a 3 or 6 gallon tank of premium fuel by Shell or Chevron. Also mix in Stabil as-per the directions. And just let the engine run, won't hurt a thing. Motor somewhere for a few hours, let it run at a fast idle while tied in the slip. And don't drain the carb bowl, or let it run out of fuel. While the gas is just sitting their until the next time you run the engine, the Seafoam mixture is still working it's magic. After a few heavy doses, then continue using in a maintenance mixture. I always mix in about 1/3 of a can in my 6 gallon tank on my 5 HP Honda. It starts easy, usually one pull, and will idle forever, even in gear!. The Seafoam cleans out all the little passages in the carb and keeps everything clean. It also removes the carbon from the combustion chamber, rings, and valves on a 4-stroke. Try it before you start adjusting or rebuilding. I'm currently performing my Seafoam snake-oil mixture in a little 2 HP Honda someone gave me because it was frozen up and wouldn't start. I've got it running, but it still won't run wide open smoothly,(but it will idle beautifully!) so she's sitting and letting Seafoam work her magic in the carb.

By the way, I would take your 6 HP Tohatsu/Nissan/Mercury,(all the same engine made by Tohatsu), over my 5 HP Honda any day! The Honda is a "nice" engine, don't get me wrong, and very economical to run, but my experience has been the Tohatsu's run smoother, and the biggest issue, they so much more quieter!

Don

Winkfish · Nov 6, 2012

Draymond, exactly what does your motor do? Does it lose power or run rough? Does it run differently at different speeds, for instance at low speed does it run well, but when you give it more power it starts to stall or miss? As many details of the problem you can give would help.

I've got a 1985 Merc outboard, still runs very well, knock on wood. I did a Sea Foam "treatment" when I first bought the boat and motor. It is a way to clean out any old carbon buildup that may have accumulated. If you're interested in trying that, I'll post the directions. After that, I used Sea Foam and Stabil when I fill the tank.

Winkfish · Nov 6, 2012

Just saw Capt Don's post. Very similar to the treatment I did, except I used one can (16oz) of Sea Foam in 3 gallons of fuel. Run the motor for 15 minutes, then let it stand for 15 minutes. Repeat that cycle 8-10 times. That will clean out any carbon buildup in your motor and should help immensely. Be warned, it will smoke a lot, but that means it's doing what it should.

If my memory serves, I think AllUGet did that and it worked for him.

Merlin Clark · Nov 6, 2012

If the other suggestions don't get you where you need to be then you might check out the "slow jet" Draymond.
http://www.tohatsuoutboardparts.com...Catalog MFS4B-5B-6B (2005) - (00221046-4).pdf
This is the Illustrated Parts Breakdown (IPB) for a 2005 model (looks like the model changed in 2011) 6hp 4 stroke Tohatsu.
In figure 3 you'll see the IPB for the carb and reference number 1-3 (3-1-3 in the table below) is the "slow jet".
The slow jet controls the fuel at idle and low speed. The part is acessible without pulling the carb. If you pull it you'll see a hole/channel thru the screw and there is a tiny hole that goes from that channel to a dimple at the end of the screw. If this is plugged it'll cause the motor to die after the priming fuel runs out. You'll need a tiny, stiff wire to poke throught this hole and push out the gunk.
I learned this here at SBO after taking the carb and pump apart twice and replacing my fuel line.

RichH · Nov 6, 2012

Been there, done that, and have the tee shirt. Tohatsu and other 4cyc small HP engine are EXTREMELY sensitive to carburetor deposits .... from BAD gasoline.

Best advice is ONLY to use 'ethanol free' gasoline ... you might have some luck in this in Maryland if you 'know' some general aviation friends.
Otherwise, add stabilizer and ONLY use 'crap-gas' that is LESS than 30 days old ... buying it ONLY from a high-turnover fuel source .... a 'busy' gasoline station such as on Rt. 50, etc. Under NO conditions use any gasoline that is more than 30 days old unless you REGULARLY add ethanol compatible stabilizer to the fuel (and then minimize the amount of stabilized fuel you do use - absolutely 'fresh' is better. Any gasoline over 30 days old goes into your automobile.

Add a purge valve to the carb. bowl, run the engine dry and then simply drain the bowl of 'residuals'. For more than 30 days lay-up, get a syringe, open the purge valve or drain plug and WASH OUT the bowl with Isopropyl Alcohol - IPA, fully drain and close up, etc.

*Start* with a fully CLEANED OUT carburetor done by a 'reknown' local OB shop, who can easily and precisely reset the fuel/air ratios. Once done, use the above 'formulary' for when using ethanolated 'crap gas'.

Also a damn good idea to complain loudly and strongly to your local MD state legislator / senator, and ask them WHY MD is one of the few mid-Atlantic states that prohibits ethanol-free gasoline for marine usage ... which is causing massive grief and possible harm to marine users of gasoline. Enlist all your dock buddies to do the same.

Winkfish · Nov 6, 2012

draymond said:
I am noting every comment and detail. Winkfish: It starts, runs and after using it about 8 times, it acts up. When it acts up, it will start and push the boat and then start stalling out. Once it starts stalling out, you can get it started but under load it will quit. It will also idle for a while and quit. Under load it quits quicker.

It sounds a little like a fuel delivery issue. External tank? Check for a clog in the pickup tube. Do you have an inline fuel filter? Check that. As you run it more, you may be getting trash buildup and starving the engine of fuel.

I thought about the possibility of a small air leak in your fuel line, but the confusing bit is that it runs fine, then runs bad, and then after a period of non-use, it runs fine again for a while. Is that correct?

If you have old fuel, try draining it and getting fresh non-ethanol fuel. Then try the Sea Foam treatment.

Winkfish · Nov 6, 2012

Also, once you get it sorted out and running, try to run your motor, even just at the dock, once a week for 15 minutes or so. Extended non-use can ruin an outboard.

Merlin Clark · Nov 6, 2012

This is a pretty quick evolution, just make sure you have the right screw. I've put a dab of nail polish on mine so that I can find it w/o the IPB in case I have this problem away from the dock.
Hopefully this works for you. Draymond.
Cool boat BTW, Cape Dories are up there on my favorites list.

MrBill_FLL · Nov 6, 2012

fwiw: http://pure-gas.org/

real gasoline by state. --doesn't list marinas (always).

and I've always ran the gas out of lawn mowers, and other small engines... that don't get used often.

MrBill_FLL · Nov 6, 2012

draymond said:
I am noting every comment and detail. Winkfish: It starts, runs and after using it about 8 times, it acts up. When it acts up, it will start and push the boat and then start stalling out. Once it starts stalling out, you can get it started but under load it will quit. It will also idle for a while and quit. Under load it quits quicker.

one other obscure problem I've found is a torn/ripped fuel pump diaphragm. it would run fine w/o load, but would stumble and stall once more throttle was applied (like an air leak).

fwiw, those glass 'puralator' in line filters are a common source for air leaks.

just throwing out ideas, and some lessons leaned.

-still want to know what the mechanic did that allows it to run fine for 7 outings, but starts to fail after that...

Winkfish · Nov 6, 2012

Draymond, When I bought my boat in 2006, it had one of those little in-line filters you can get at Wal-Mart or Academy Sporting Goods. Easy to change and install, and it did fine by me. Earlier this year, I had some work done on my motor and the mechanic put in a larger inline fuel filter/water separator. Still works fine.

If you're asking about doing it yourself, it is not a hard thing to do if you're at all mechanically inclined.

shemandr · Nov 6, 2012

draymond said:
Has anyone put an inline filter in the hose from the tank to the engine?

yes - for a Nisson 2 stroke 3.5 hp I also rebuilt the carb and put a new float bowl because the finish was flaking pieces which were clogging the jets. It went from an engine I almost deep sixed (I mean pushed off the back of the dink) to a pretty nice engine that I am still using. And I don't know anything about engines. In the Nisson its a gravity fed fuel line.