need some mercury help

bummy80

Cadet
Joined
Sep 23, 2006
Messages
9
i have a 1988 2.5 mercruiser inboard that has been sittting for a couple of years. did the usual carb rebuild, drained the gas, new points and condenser, plug wires and spark plugs. also i cleaned the distributer inside, set the dwell and timing to specs. the problem i am having is running the engine on muffs i get a miss, bogging, and or gas misting out the carb at about 3/4 throttle. my tack does not work correctly so i am guessing it is about 4000 rpm and the max wot is about 4200 by the specs. my question is is this normal being run on the muffs with no load on the boat or do i have a problem somewhere? running out of thing to check or try.
 

Alpheus

Lieutenant Commander
Joined
Aug 3, 2009
Messages
1,759
Re: need some mercury help

so i am guessing it is about 4000 rpm and the max wot is about 4200 by the specs. my question is is this normal being run on the muffs with no load on the boat or do i have a problem somewhere?

You are kidding right? If you ran your boat at 4K RPM with no load its time for a new engine...

I would say you got a problem somewhere.

Dont do that!!!
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,363
Re: need some mercury help

possably a melted impeller not to mention floating the valves.
 

bummy80

Cadet
Joined
Sep 23, 2006
Messages
9
Re: need some mercury help

it sounds bad the way i explained it, i was just testing the throttle response. i just did it a few quick times. my question is does it being in the water have a difference on the tuning?
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,363
Re: need some mercury help

Being at "no load" is not the best way to check an engine.The issue with hi rpm`s on a hose is that the pump cam actually suck so hard it shuts the water flow off from hose collapse, the impeller burns ,and now the hose is forcing water thru the system instead of sucking it. Once in the water you have a overheat condition.
 

bummy80

Cadet
Joined
Sep 23, 2006
Messages
9
Re: need some mercury help

thanks for the reply, that answers some of my questions.
 

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: need some mercury help

Night and day difference between running on hose and in the water!
 
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