86 Mercury 60hp Idol and Low speed seems fine, Full throttle only hits~3000-3500RPM

[dpmsgeek]

I have a 1986 60hp Mercury idols pretty well and drives around at low speed. When I push the throttle up the motor spins up to ~3200 - 3500rpm and doesn't go any faster even when I push the throttle up all the day. The boat was previously running around 5000 - 5200rpm. Compression on all three cylinders is about 125. Spark looks good as it will jump a decent distance from the plug to the boot. I rebuilt the fuel pump with the quicksilver kit and also replaced the primer pump. Butterfly's and linkage seem to operating properly. The carbs were cleaned by a local marine shop at the start of summer when they diagnosed and replaced a switchbox. I hope someone can help me get this thing running better.

 

[gm280]

:welcome: aboard dpmsgeek to iboats. Glad to have a neew iboater...

I realize you stated that the carb(s) were cleaned by a local marina, but I suspect the carb(s) are still your problem. If you know for sure that the advance and spark are absolutely working properly, then I would redo the carbs and pay special attention to the high speed jet systems. But without any more info or being there and testing things, that is my opinion.

 

[dpmsgeek]

Does anyone know where to find a service book for rebuilding the carbs and working on the motor? I tried the SELOC brand online guide and I was very disappointed.

 

[dpmsgeek]

No Title

Which jet handles the high speed fuel?

 

[dpmsgeek]

Update: Rebuilt the carbs and it ran pretty well after getting it warmed up and I could get it up to 5000-5100rpm. Then at low idle it wanted to die out. If I primed it some more I could get it back up and running. I'm trying to figure out why it's loosing prime and I'm guessing it's linked to my running issues.

 

[dpmsgeek]

Just realized that the vent was shut on the gas tank. Would that cause it to loose prime?

 

[GA_Boater]

Just realized that the vent was shut on the gas tank. Would that cause it to loose prime?

It's not loosing prime. It can't suck fuel out of the tank when the tank vacuum overcomes the ability of the fuel pump to draw fuel.

Wasn't the bulb flat or nearly flat?

 

[dpmsgeek]

Bulb was not flat at all.