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I think I've done something to my 1976 7.5 HP Mercury Thunderbolt

S

Stani

New member
Hi there........

I just recently installed a new waterpump impeller on my 1976 7.5 HP Mercury Thunderbolt. The motor was running great a few years ago but then it sat for a while (A few years). I took it out of storage a few weeks back but the water pump was not pumping. So after some internet searching I fund a replacement impeller and installed it. I thought all was good till I got the boat into the water today. It starts up fine and the water pump is working beautifully but I can't seem to get any speed in first gear. When I rev it in neutral I get some high revs, same goes for the reverse. But I can't seem to get it to rev up in forward???:confused: It just goes put put put. My daughter wants to call the boat "Put Put" now.

I think I might have installed something backwards.:mad: If thats possible.

Any leads or insights would be greatly appreciated.

Thanks:)

..........Stani
 
It sounds more like your carb has got clogged up during it's "sit".

When a motor isn't under load (not in gear/trying to push a boat) if it runs fine but almost dies when in gear that is almost always the result of a fuel restriction.

Since it's been sitting a clogged carb would be high on the "possible" list along with a clogged filter (if present), bad fuel line or connector, worn/rotted diaphragm in the fuel pump etc.

Motors like to run. When they are laid up for long periods they require much more maintenance than one that is run constantly.

I would start by pulling/cleaning the carb and inspecting/replacing any parts/gaskets etc that look suspect.

You might get away with a tank of new gas and some Seafoam (or the like), but 9 times out of 10 "tune up in a can" won't fix the issue.
 
Hi there everyone..............

Got the motor at home now. I'm gona drop the lower unit first. Anyone have any pointers on how to reassemble the lower unit so that the spline of the shift shaft line up correctly? Any help is appreciated.

Thanks


..........Stani
 
ARRRGH:mad::mad::mad:

I can't seem to get the shift shaft spline to align. It always ends up with the 1st gear somewhat in the neutral position so that the actual neutral is about halfway in-between the neutral and reverse. Any tricks or secrets to get this right. It seems to be getting the best of me.

Thanks:)
 
I dont know if your is the same but when i put it back together i always leave it in fwd gear. Goid chance it will work.
 
Reassemble it upside down--seriously. Use a mini light to see if the shifter (coming from up top) is centered in the hole. If not, poke at it with some wire--there's an opening just below the Dyna Floats.

Jeff
 
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