Does anyone know anything about outboard motors?

Question

I have a 90 hp outboard Yamaha, when you give it gas it seems it does not want to get up on plane. Almost like it dragging butt.

Please Help

Answer 1

Classic symptom of clogged hi-speed jets.  Seafoam is great stuff, I put an ounce per gallon in every tank - it helps condition the fuel and keep carbon from building up in the cylinders.  

But seafoam isn't a strong enough solvent to clean your carbs - anything that strong would just strip the lubricating oil right off the cylinder walls.

The only way to clean your carburetors is to take 'em apart and soak 'em overnight in carb cleaner (I use B-12), blow out all the passages with compressed air (or aerosol carb cleaner), and reassemble with new carb kits.

If your carbs have adjustable slow speed jets, post another question on how to set 'em when you get to that point.

In a case like this, I prefer to do a compression and spark test before tearing into the carbs, just in case.  You're looking for even compression across all cylinders - lowest PSI within 5% to 7% of the highest.

Use an inline spark tester and set the gap for 7/16" and look for a strong blue spark on all cylinders.  That will rule out any electrical problems including powerpack.

And *DON'T* run the engine until the problem is corrected - any cylinder that's starved for fuel is also not getting any lubrication.

Good luck!

Answer 2

not enough info. boat size and type, prop, load in boat, trim, should turn 5000 rpm at no load etc. . is bottom clean?

Answer 3

simple its a powerpak.

start it in the water and pull a plug wire off one at a time and the one that dont seem to make a diff, its gone south. also make sure the motor is level so you dont flood  with gas when you are acelerating tilt as you gas then plane out. you probily are tilt the motor all back and trying to leave on a flooded motor.

Answer 4

Varnish in carbs caused from sitting too long without running. Easy fix. Don't take anything apart to clean it.  Go to NAPA or almost any auto parts store and get some stuff called Sea Foam. Put the recommended amount in the gas tank and drive until it starts to clean up.

this used to happen to us every year until we started putting stabilizer in the gas in the fall.

This also happens to motorcycles.