Logo
FULL SITE MENU

Not enough rpms 1980 80 merc.

J

jerry123

New member
Recent purchase 1989 80 hp merc. #oc204123 had low comp. Decarbed now @ 90 lbs. # 1 100 # 2 105 # 3 tested on trailer in water and although it seems to run smooth it doesnt rev. As high as it should.
Boat has no tack. While decarbing running in water it would not flood out top carb but would lower 2 carbs. Hooked up sparkplug tester between coil and plugs 7/16 across all 3. What should i test next ?
 
Re: Not enough rpms 80 merc.

If you are saying you sprayed " mechanic in a can " into the top carburetor. It had little or no affect on the motor and it nearly stopped the motor while doing this on # 2 and 3.---------I would suspect that # 1 cylinder has a problem, either reed valves or blockage in the carburetor.
 
Re: Not enough rpms 80 merc.

;)My suggestion,don't rev her out in the tank and DON'T rev her on the muff's. From what you say you need a carb rebuilt,a honing and new rings;);),and a blast of powertune.If you are unlucky,you'll need a rebore,but try above first.
 
Last edited:
Re: Not enough rpms 80 merc.

How are the carby linkages have you checked that they are pulling the carbys fully opened and also evenly. 100 PSI isnt too bad it indicates most likely rings but you could pull it apart now and find more damage or just a set of rings with a hone, or simply run it for a season first
 
Re: Not enough rpms 80 merc.

Another possible suggestion may be to check your electrical if youve got a weak coil, coilpack it wont reach the higher RPMs either, also check wires and plugs, probabley knew this part. If you can look at it at night, it really shows up on wires, if they're bleeding out.
 
Re: Not enough rpms 80 merc.

hondamotorcycleguy said:
Sorry didn't see you had tested electrical
Click to expand...


You would be surprised what an incorrect spark plug gap can do too, the exact problem happened to me a few weeks ago it started fine but when you rev it she was sluggish and sounded like it was running on 1 cylinder. Also have a play around with the air/mixture screw that smooth my idle out nicely
 
Last edited:
Re: Not enough rpms 80 merc.

Just 90 lbs compression means that cylinder is fried. The other ones aren't too great either. Time for a rebuild. Sorry.

Jeff
 
Back
Top