Need some advice

[mark]

" Hi,
I have a 1988 rebuilt Y

" Hi,
I have a 1988 rebuilt Yamaha 85 new pistons the lot after having it rebuilt it was sitting on dry dock for a long time when i put it back in the water it trottles half way and as you push down further it shuts down you pull back to half and it goes fine again then recently when you start up it goes 100ft then cuts out you prime the bulb it starts goes another 100ft and cuts out again prime again goes 100ft cuts out. "

 

[jon]

" Mark,

I can't t

" Mark,

I can't tell, from what you've said, if you ever broke that motor in after it was rebuilt, and I don't know exactly what the break-in procedure is for that motor, but it's something you'll want to think about after you get it running right.

Because of what you've said about keeping it running while pumping the bulb, It's almost definitly a fuel problem. The one thing you may want to try before you trouble-shoot is using some new gas (especially if what you are currently running has been sitting for over a couple months without stabilizer, or if it has been sitting for over a year with stabilizer).

I'm not familier at all with that motor, but the first thing you probably should suspect is the fuel pump; if it runs correctly as you pump the bulb, you are acting as the pump. It is also fairly easy to eliminate the fuel pump as a problem, so I would look at it first.

If it turns out not to be the pump, and it is not an obstruction, or air-leak allowing air into the line, you could be reasonably sure it was a clogged carberator. Depending on how long it was sitting, it may also be a combination of multiple fuel problems (ex. clogged carb/faulty pump or sour fuel/clogged carb/cracked hose).

After letting an engine sit for a lengthy period of time, varnish can build up in the carb, which will often block passages that the fuel flows through, and also cause moving parts to stick. When you throttle it, the fuel/air mixture becomes too lean, because of the lack of fuel flow the motor is stalling out. In this case a carb cleaning/rebuild would be neccesary. "

 

[mark]

" 85 Yamaha been on dry dock f

" 85 Yamaha been on dry dock for some time went to start engine turning over very slow took out plugs sprayed C.R.C in piston cylinders turned key with plugs out, engine turned a bit faster put in plugs turned very very slow again took all power out of battery I wonder if it could be the battery cables leading to the engine do you think that they might be rusty on the inside of the casing hence loosing curent to the engine? we tried the bare cables on a volt metre and they read 12volts going through but i wonder if under load the engine is not getting enough current "