I have a 40 hp Tohatsu 2 stroke on our Pontoon boat up north. The idle and low rpm performance are OK, a bit on the rough side but when you go to more than about 1/4 throttle the engine starts to die, if it doesn't die it sounds like it is under a tremendous load, almost sounds like a misfire, and then after anywhere from 5-30 seconds it works the issue out and runs well until you pull the throttle back and try to accelerate again. This issue started at the end of last season and unfortunately did not fix it self over the winter (I can dream, right). I have replaced the plugs (2 cyl) and always run fresh fuel mixed 50:1. Any ideas?
Outboard Issues
- Thread starter scott_b
- Start date
snowfish
Member
Does it accelerate better if the choke is partially closed? If so, your jets are partially plugged. A healthy dose of SeaFoam should clear it up. Same thing happened to my Evinrude 25. May take a few runs. The Evinrude took almost a full tank to get the jets open. Each time out the choke needed to be closed less and less until it was running normal again.
Also, even if you run fresh gas, there could be water in the carbs. My pontoons 60 Merc was giving me fits because of this. Find the carb drain plugs & pull 'em. My Merc has large brass hex head plugs on the side of the carbs. Not sure about Tohatsu. Use the primer bulb to flush the daylights out of it. No more problems with either one.
If it was me, I'd do both the SeaFoam and Carb flush and see what happens. I usually run a slash of SeaFoam in every tank.
Cheers.
Also, even if you run fresh gas, there could be water in the carbs. My pontoons 60 Merc was giving me fits because of this. Find the carb drain plugs & pull 'em. My Merc has large brass hex head plugs on the side of the carbs. Not sure about Tohatsu. Use the primer bulb to flush the daylights out of it. No more problems with either one.
If it was me, I'd do both the SeaFoam and Carb flush and see what happens. I usually run a slash of SeaFoam in every tank.
Cheers.
Yes, I always advise folks to get plenty of advice!
Naw, just get in line with all the other folks waitin' to catch my next screw up!
only way to do right is have the carbs cleaned,drain fuel system.use only premium without ethanol .shelf life of ethanol is only thirty days and will plug jets especially the smaller 4 stroke idle jets! just draining the carbs does not clean the jets and could lead to serious engine damage!running fuel additive is a good idea after cleaning the carbs! .02 worth
AMSOIL has a new fuel additive out for 2 & 4 stroke small engines called Quickshot SE. You can try it and see if it cleans it up. Its supposed to be a really good product. Use 8oz bottle per 6 gals for cleanup and 8oz per 12 after that as a short term stabilizer and treatment against further ethanol problems.