Intermitent Power Loss

[jd438]

I have a 1989 70 hp Merc that loses power randomly at WOT. Sometimes it runs great, then the next time it will open up for a while then slows to 2500-3000 rpm. If I push the choke she speeds back up. Ran a can of Power tune through it and same thing. New fuel lines and fuel filter. Any ideas on what would cause this?

 

[Laddies]

Re: Intermitent Power Loss

If choking helps you need to clean the carbs.

 

[jd438]

Re: Intermitent Power Loss

I pulled them all off and took them apart and didn't see anything in them, but still used a bunch of carb cleaner in them. Took it out last night and ran great. Need to tweak the idle a bit as it seems faster now.

 

[j_martin]

Re: Intermitent Power Loss

Check the fuel tank. One of those durned foils off'n an oil bottle will float around on the bottom and occassionally get over the fuel pickup. Other debris can do the same.

been there, done that.
John

 

[jd438]

Re: Intermitent Power Loss

It's not that, two new fuel tanks and I switched and it did it until I cleaned the carbs. I started buying the gallon jugs and use a mixer bottle so I don't get that in there.