75 Merc 110 9.8 bogs in forward screams in reverse

harrygriffin

Recruit
Joined
May 30, 2010
Messages
2
I have a 1975 Merc 110. 2 years ago it seemed to run reasonably strong. Since then the engine seems to really drag in forward. I rebuilt the carb last year. Just got it out today and put it in the water to run the engine and make sure it is working ok. It started reasonably easy but when i tried to rev it up in forward it would only go about 50% rpm. I tried reverse and it was very responsive and revved up very fast. I put it back in forward and it just bogg and didn't seem to want to run very fast.

I can't see this being the motor as it runs so strong in reverse but doesn't want to do anything in forward.

Any suggestions?
 

harrygriffin

Recruit
Joined
May 30, 2010
Messages
2
Re: 75 Merc 110 9.8 bogs in forward screams in reverse

My confusion is it runs so well in reverse. Engine has full range of rpms and responds very quickly. Put it in forward and it bogs half way through the rpm range.

If the carb was bad, it would be a problem in forward or reverse.

I wonder if there is a problem in the bottom end that is binding something?

Harry
 

btcox123

Cadet
Joined
Jan 10, 2009
Messages
23
Re: 75 Merc 110 9.8 bogs in forward screams in reverse

IMO,
A prop "makes it's power" in forward, in reverse the prop spins with much less resistance. Think of it as in forward its like an automobile on dry payment, in reverse its like an automobile on a muddy road. Their is much less resistance and therefore not as much power needed to get the RPM up.
I would also say clean the carbs, set the floats, make sure your getting good clean fresh fuel to the carbs. Fresh set of spark plugs, and maybe a timing/Synchronizing/Adjusting per OEM manual.
good luck.
 
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