1979 Merc 7.5 issues

Bubbles Up

Petty Officer 2nd Class
Joined
Aug 4, 2009
Messages
106
Hello all,

I am new to the boat ownership world as an adult. I got a good deal on a 1979 Merc 7.5 (s/n 5145529) and a 12 foot aluminum car topper.I will try to be as descriptive as I can.

I had the engine serviced because it was sitting ofr a few years in a garage. I had the carb cleaned,new plugs(NGK) and a new impeller and the starter rope fixed.Along with a grommet (cooling related) and a seal replaced (crankcase?) the leg oil was also serviced. The fuel tank that was included I cleaned it out(steam cleaned) and alcohol dryed a new fuel pickup and to the motor is all brand new.I run a 50;1 fuel mix (Merc 2 stroke + premium fuel)

The issues it seems to be that when I troll that after 20-30 minutes it will stall sometimes it will be 1 pull and back running for another few minutes other times I can pull that starter rope 20 times then it fires up.

Another issue is that when I open the throttle wide open it seems like that the motor revs up then it is like a "transmission" slipping then it seems to catch fully then produce power/speed. When I reverse I can hardly back away from the dock,I can rev the engine quite high and no real difference.

My fishing buddy has a Honda 7.5 4 stroke (1978) I can come nowhere near his speed or power and he has a Lund. My full throttle is his half!

Your expertise will be greatfully be appreciated. If I have missed something pleas ask and I will do my best to answer your question(s).
 

green4themoney

Petty Officer 1st Class
Joined
Jul 21, 2004
Messages
318
Re: 1979 Merc 7.5 issues

well first of all, your slipping issues is most likely your rubber hub insert in your prop, when these go, your prop will slip in the water on the shaft under any sort of load, the random stalling sounds like an electrical leak somewhere you may have a shorting stop switch ive seen this before, you will have to get your prop re-hubbed more then likely
 
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