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Early 90's 70 HP Force - Leak in Crankcase Halves

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WoodyL

New member
I am brand new to this forum. Sorry if this has been covered.
Mechanical background is pretty "novice" but I have taken on some DIY projects (for instance successfully replaced starter in this outboard a couple years ago).

Our Force has been stalling and stopping at slow speeds, then we cannot get it to restart. We have also had problems with it stalling a full throttle.

Took it in and the mechanic diagnosed a leak in the crankcase halves. Specifically, the mechanic said compression was a little low on the top cylinder but acceptable. Spark was OK. Starts and runs but runs lean then backfires and quits.

The mechanic said "get a new motor. It's a Force and not worth fixing"

We have been searching online for advice about possible repairs, and with nothing to lose but the time it would take to attempt a fix, we are wondering if
a) this diagnosis sounds correct
and b) is this something that a novice could take on with some good advice or instructions.

Any input would be appreciated.
 
Low comp??? What were the #s
Leak in the crank case halves?? Where and maybe a pic or 2

Sounds like the "mechanic" isn't as good as he thinks??
Nothing wrong with Forces.

Stalling at full is usually a fuel delivery problem.
Stalling at idle : what's the rpms in gear at idle? 750-800 is good.
The air screw should be set at 1 and 1/8th out.

Answer the questions and any other info you can add and we'll try to help.
 
Jerryjerry05 said:
Low comp??? What were the #s
Leak in the crank case halves?? Where and maybe a pic or 2

Sounds like the "mechanic" isn't as good as he thinks??
Nothing wrong with Forces.

Stalling at full is usually a fuel delivery problem.
Stalling at idle : what's the rpms in gear at idle? 750-800 is good.
The air screw should be set at 1 and 1/8th out.

Answer the questions and any other info you can add and we'll try to help.
Click to expand...


We took this to a marine dealer near us. We were in a couple months ago but I called today and talked to the mechanic. He doesn't recall and didn't write down the compression but mentioned it should be "within 10%" and it was in that range. Don't know if that makes sense.
We do no know what the rpms is in gear at idle.
The mechanic said air is getting into the fuel mixture and the motor would need to be disassembled and crankcase resealed.

I can send pics if that would help but would need to know what to take photos of specifically.

Just to reiterate....I'm not a mechanic but figure we have nothing to lose if there's something we can tackle ourselves.

Thanks for your reply.
 
IF???? You can handle tools you can do it.

Before you start.
Get the motor running.
As it runs, spray starting fluid around everything but the front of the carbs.
If it affects the way it runs when you spray then it's sucking air.
Post the results.
I thought he'd told you were it was leaking. That's why I asked for pics.
 
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