5 hp force compression

Markrhoyt

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Sep 1, 2011
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Does anyone know what acceptable compression reading is for a force 5 hp outboard?
 

JB

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Re: 5 hp force compression

Both cylinders within 10% of each other and over about 60psi. Testing should be done according to the thread in Engine FAQs.
 

jerryjerry05

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Re: 5 hp force compression

Only 1 cylinder.
Depending on the guage???
You can have readings from 100# up to 150# The higher the better!
But that depends on the guage.Cheaper vs expensive.???
Remember to advance throttle(if possible) when testing and ground out the plug wire.

Always include model# Serial#.
Profile,location?
 

Markrhoyt

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Sep 1, 2011
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Re: 5 hp force compression

It is a single cylinder, dont have the serial number with me right now. It reads 55 lbs on an expensive compression gauge. Good spark, good fuel, will only pop once in about ten pulls but will not run. Checked the reeds they are excellant.
Rings? Head?
 

JB

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45,907
Re: 5 hp force compression

Matching cylinders wouldn't work for that one. I guess I shouldn't assume information left out. :redface:

I wouldn't blame 55psi from a rope start outboard for your trouble. I think it should run if it has correct fuel and timing. Check the carb and ignition timing before you start tearing it apart.

You might go to the Engine FAQs forum and do the "Outboard won't start" article to narrow down the suspects.
 

jerryjerry05

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Re: 5 hp force compression

Spray some oil in the cylinder and see if the compression goes up?
Possible the rings are stuck and it results in low comp.
 

Markrhoyt

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Sep 1, 2011
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Re: 5 hp force compression

Ok, found the reeds to be distorted and the rings frozen. And of course the rings broke trying to free them, so where can i find the parts? A couple places on the web said they are no longer available but there has to be someplace to get them.
 

jerryjerry05

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Re: 5 hp force compression

Gotta know????
Year??
Serial#
Model ?

They made Forces from 1984 to 1999 a lot of years to choose from???

Parts are out there.
Reeds might be tough to find?

Try Franz Marine.
 

Markrhoyt

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Sep 1, 2011
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Re: 5 hp force compression

Dont know the year or model. The only info on it is a sticker on the block with serial # OE117205
 

Markrhoyt

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Sep 1, 2011
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Re: 5 hp force compression

Thanks Jerry, called Franz Marine and they had the parts in stock and they are on the way.
Thank you guys for the help.
Mark
 
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