Yamaha 25 HP 2stroke outboard cannot get it to go fast?

Question

When I have it in neutral I can rev the engine up high. However when engine is in forward gear I can't get it to go at high speeds. Probably can get it to about 1/3 of the speed it has gone in the past. Engine has no problem trolling all day long at trolling speeds.

Do I have a carburater problem? or what?

Answer 1

problem with running carb cleaner through a two-stroke is, any solvent strong enough to clean the varnish off a carb will clean the lubricating oil right off the cylinder walls.

If you wouldn't run your engine without oil, don't run it on carb cleaner.

Only one way to properly clean a carburetor:  remove, disassemble, soak overnight in carb cleaner (I use B-12), blow through passages with compressed air (or aerosol carb cleaner), reassemble with new kits, reinstall, link & sync, adjust slow speed mixture screws (if equipped).

That'll fix ya up.

*DON'T* run it like it is -- whichever cylinder is starved for fuel is also not getting any lubrication.

Answer 2

It is probibly 1 of two things. Firt..it might be your carb/s dpening if it has two cylinders or not. The carb has probibly collected lacker (what gas and oil leaves behid when it dries up) in the jets so it is not giveing it enough gas to get up to full power. You might want to try to run some Chemical B-12 though the engin, it wokres the best and at the end of every boating seasion run it though the engine.

2. It might be a spark advance problem. You would have to check to see if the spark is good and might need to replace the spark system. I had a 50hp 2 stroke and thats what went bad in it first and it did the same thing.