Mercury KH7

[bktheking]

I'm going to aquire this motor in January. Doing some research (which there isn't a lot of info on them) I stumbled upon a youtube video of a gent who explained that the water pumps were undersized in these motors and that they overheated. He went on to state that Mercury had a factory recall where customers could bring in the motor and Merc dealers outfitted them with a newer style water pump. He went on to explain that he drilled an additional set of hole as I gather that he did the conversion himself. Can anyone explain to me how to tell if it's been done without pulling the pump. Is this something I should do if the motor I get doesn't have the new pump? Any additional info appreciated.



Thanks to all.

 

[Chinewalker]

Re: Mercury KH7

Nice find! Not quite the Holy Grail of old Mercs, but rare enough! Did you get the lower cowling with it? I bought mine for $10 at a garage sale about 15 years ago. It needed a rebuild - one piston badly stuck. Runs great now! Flat out flies on my 12-foot DuraNautic.

I've never had a problem with my Cruiser as far as pumping water goes. It does have the original lower unit on it, too. You can tell on the units as the original will have the intake holes on the BOTTOM HALF of the gearcase bullet. The later units have the intake holes on the top half, with a single, small hole down low to allow draining. That single hole often got plugged with silt and allowed that cavity to fill with water. That's why so many of those units have the rear cap blown out, usually taking the housing with it...

I also drilled a small hole, at an angle, into the bottom of the rear water jacket cover to allow a pee-stream to shoot out where I can see it. I think later 20-cube models already had that hole there...

 

[bktheking]

Re: Mercury KH7

Nice find! Not quite the Holy Grail of old Mercs, but rare enough! Did you get the lower cowling with it? I bought mine for $10 at a garage sale about 15 years ago. It needed a rebuild - one piston badly stuck. Runs great now! Flat out flies on my 12-foot DuraNautic.

I've never had a problem with my Cruiser as far as pumping water goes. It does have the original lower unit on it, too. You can tell on the units as the original will have the intake holes on the BOTTOM HALF of the gearcase bullet. The later units have the intake holes on the top half, with a single, small hole down low to allow draining. That single hole often got plugged with silt and allowed that cavity to fill with water. That's why so many of those units have the rear cap blown out, usually taking the housing with it...

I also drilled a small hole, at an angle, into the bottom of the rear water jacket cover to allow a pee-stream to shoot out where I can see it. I think later 20-cube models already had that hole there...

I'd does not have the lower so I set out to find one, bought an original from a gent out in Kentucky with paint and FNR in tact for next to nothing, even has the dzus fasteners attached. I agree it's not the holy grail like a KG7Q or H but it is rare IMO, 1st and last year they made them and the production numbers were relatively low plus it's got the twist grip and and shifting. I haven't got the motor yet, going to get it in January, anything to watch for besides the obvious?

 

[Chinewalker]

Re: Mercury KH7

Biggest issue on mine was getting the magneto to work right. It has the Bendix-Scintilla magneto, which can be a pain to get right as new points are nearly impossible to find and coils are pricey. Not nearly as good a mag as the Phelon that replaced it. Once I got the bugs ironed out, it mostly worked fine, but still tended to drop a cylinder when cold. If your coils are cracked, bite the bullet and put the new ones in there. The olds ones will only cause you grief, no matter how well you reseal them.

The detents that hold the shifter in place on mine were a bit worn, too, so it tended to drop into forward gear - generally at inopportune times, like when docking, etc. I ended up bending the spring tab a bit to put more tension on it...

Other than that, it ran like a scalded cat!

 

[bktheking]

Re: Mercury KH7

Everything under the flywheel was replaced in 2004 including the impeller and has had virtually no use since, I'm not paying $15 for it either for that matter and i'm supposed to get a demo when I pick it up, so far so good!