78 Evinrude 35hp

[kickask]

I have a 78 Evinrude 35 hp that had not been started in about 5-6 years. I changed out the gas and had trouble getting it started, left it sit a couple days and then was able to get it started right up. I have been running every couple days but am still having the same issue. It "coughs" intermittantly, especially at lower throttle. When I throttle up it run strong, and then when I back down it sputters again. I changed plugs, bought a new gas can and hose and added seafoam. Seems to be slowly getting better but continues to sputter. Is this a matter of cleaning the carbs since it was sitting so long? Can carbon build up be run out? The motor was professionally rebuilt prior to sitting. Remacined and oversized pistons, new electrical, impeller, etc. Probably had 10 hours tops since being rebuilt. Any suggestions would be appreciated.

Thanks
Tp

 

[HighTrim]

Re: 78 Evinrude 35hp

Welcome to iboats.

Spitting back or coughing, sounding like a mild backfire, indicates a carb slow speed restricted jet..... something causing a lean carburetor scenario.

It will need to be bathed, cleaned then rebuilt.

Check out the FAQ for a thread entitled, "Awakening a Sleeping Outboard", as there will be more to do than simply the carb.

 

[tashasdaddy]

Re: 78 Evinrude 35hp

you also need to do a water pump service. that impeller is old and dried out.
carb instructions: the difference is you have an adjustable low speed jet
http://forums.iboats.com/showthread.php?t=244013

you could try this, before the carb rebuild.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
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[kickask]

Re: 78 Evinrude 35hp

Thanks for the replies. I'll give it a go.