Mercury KH7 won’t fire

[mercuryman]

I have good spark, 120 psi compression. Squirted fuel in the carburetor no fire and plugs look dry. Removed plug and
squirted gas in cyl them it will fire a few times. Can the reeds be stuck I was told it has been sitting 15 years.

[Pondrocket]

Need to go thru complete powerhead then rebuild carbs & fuel lines. Make sure tank is good. Yes reeds could be stuck but you will need to properly correct by going thru powerhead. All depends what your looking for out of the motor Wall hanger, Runner, Show Motor?

Travis

Travis
AOMCI VP Communications
AOMCI Webmaster
webmaster@aomci.org

[20mercman]

Most likely crank seals. It is easier to draw air through the hard crank seals than to lift the reeds.

Steve

[billw]

You can check the front four reeds by removing the carb and feeling around in there with a small, 90 degree-angled pick. They may also be stuck open a bit too much. I just had a Scott 16 where the reeds were hung open from mouse nest debris.

Long live American manufacturing!

[Doug Wilson]

From what I have seen with the KE7 I have been working on would agree with Steve. Crank shaft seals are probably shot leaking if so that is what will
happen. Found the same thing on my WG7 Wizard if you put gas in the cylinder it would fire occasionally but would not start.
When you pull the lower bearing to get to the seal check and make sure it is real smooth otherwise good time to replace it.
Joe at Ferguson-Poole has them and the gaskets you will need, Old Mercs and others may too.
Doug

Doug

how is it motors multiply when the garage lights get
turned off?

[mercuryman]

Yesterday it would not fire with fuel squirted in carb. Today I removed card squirted some penetrating oil on reeds and moved them with a screwdriver them it would fire right up with fuel squirted in carb. Put some fuel in tank choked it and it would start. Put it in the tank and it will start but won’t stay running. Switched carbs with my Wizard it will start run fast only and serge. I guess you guy’s are right I need to replace the seals. The lower seal looks hard to change how do I remove the bearings I have no special tools. My Wizard is a WH7 with the Phelon magneto will this swap with the Bendix on the KH7.

[Doug Wilson]

You will have to swap the cam, (be careful removing the cam they are hard to find) flywheel and all but should work. It is actually not that bad to change the bearing pull power head and take bottom cover lose (that is the hard part mine did not want to come off.) Heat up the plate and bearing should push out may fall out on its own. Replace seal and put bearing in freezer for a while to shrink it then should press in easily. Replace gaskets and reassemble. Trick from Joe Poole is to put a thin coat of red loctite on outside of the seal when you go to put it in. Top seal take an awl punch hole in top of seal put in sheet metal screw and pull out.

Doug

how is it motors multiply when the garage lights get
turned off?

[mercuryman]

Thanks for advice now I won’t put off taking it a part, I have some seals on order.

[Author]

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