1991 70hp Force - Small Miss at all RPM's

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bugmanjr

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Motor will set and idle and also wind up, but it has a miss in all rpm ranges. I definately think its fuel related. I think it might be the fuel pump. Does that sound like a possible cause? Was also wondering if a bad primer solenoid would cause a miss? I ask because the primer solenoid was full of trash and the lines connected to it as well. I cleaned them and tested the solenoid and it pumps, somewhat weak, but it pumps.
P.S. This is with earphones not in the water...

Thanks
 
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bugmanjr

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Re: 1991 70hp Force - Small Miss at all RPM's

Forgot to add, while its missing, if you shoot some carb spray lightly in the carb it will straighten up. When you stop with the spray it will go to missing again..
 
eurolarva

eurolarva

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Re: 1991 70hp Force - Small Miss at all RPM's

Sounds like the carbs are running lean. Above the choke butterflies is a screw for the mixture adjustment. Turn it 1/8 to a 1/4 turn counterclockwise.
 
roscoe

roscoe

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Re: 1991 70hp Force - Small Miss at all RPM's

What the other guys said.

Probably not the fuel pump.
Try squeezing the primer bulb while it is missing and see if it makes a difference.

The fuel enrichment valve (choke) only operates when you push in the key.
Works off of pressure from the primer bulb and fuel pump.

A small amount of water in the fuel will sometimes cause this type of miss also.

Do as eurolarva says.
If that doesn't fix it, rebuild the carb.
 
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bugmanjr

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Re: 1991 70hp Force - Small Miss at all RPM's

there is 2 adjusting screws on the top of this carb. I tried the metal(brass I think) one and it didnt do anything.. Then i tried the plastic one, and if i back the plastic screw until it is about to fall out it stops missing.???
what other issues could you think of?
I cleaned the carb out and the float moves freely and the main jet is not trashed up.. The fuel pump diaphrams look ok..

????
 
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bugmanjr

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Re: 1991 70hp Force - Small Miss at all RPM's

what about the coil packs? I have a open power pack so i switched around the wires to the coil packs and the apropriate plug wires to match and it seemed to straighten up a little.. i went to test the voltage with a volt meter and it arched itself off. i had the apropriate setting on the meter and the wires were plugged into the meter corectly (+ - ).
????
THanks So Far!
 
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