85 50 HP wont start

[eshreve]

Hi guys -

New to boating need some help.

I have a 1985 Force 50 HP. Has run great for the last month I have owned it, but last Sunday it would not start. Cranks fine, just does not catch.

I have done the following to try and get it running again:

Charged battery
Replaced float
changed spark plugs
tested spark and it was present
removed fuel filter and used primer bulb and fuel flows fine through it
removed all fuel lines and fuel flows fine through them all.

I do have an extra carb I could put on, but I'm not sure that is the answer.

Any and all help is welcome.

 

[pnwboat]

Re: 85 50 HP wont start

Make sure it's not flooded. Sometimes if the engine won't fire due to bad plugs etc. you crank and crank and flood the engine. Even after correcting the problem, still won't fire due to flooding.

If that checks out OK, then I would suspect points and condenser.

 

[eshreve]

Re: 85 50 HP wont start

Did dry compression test and got 60 psi. Changed the head gasket and got 90.

Motor started and ran for 15 seconds before I stopped it. After that it would not start again.

Any thoughts?

 

[john from md]

Re: 85 50 HP wont start

Pull the plugs, ground the plug wires and motor the engine to get the excess fuel out.

Clean and install plugs, do not pump ball, do not choke, make sure throttle is in idle and give it a try.

Also, were you getting nice, blue sparks?

John

 

[Jeremy90bay]

Re: 85 50 HP wont start

I believe that 120+ is good compression anything under is no good. hope I could help.

 

[eshreve]

Re: 85 50 HP wont start

so i took the plugs out and cranked the motor, it spins like crazy. i put the plugs in and crank and it jerks all around. turns the motor to your left if you are facing the rear of the boat.

i tried the screwdriver in the plug wire and got spark. got any ideas? bad plug?

 

[john from md]

Re: 85 50 HP wont start

Do you have spark on one or both plugs? I am confused by your post.

If it "jerks around", it could be firing at the wrong time. Verify that the CDI wires are connected to the correct coil.

It is also possible that the key in your fly wheel broke and the flywheel is out of time.

Check both and report back.

John

 

[eshreve]

Re: 85 50 HP wont start

been using the boat non stop since monday. home today from the lake to work. then back to the action tonight.

anyways here is what all was fixed to get it running.

flywheel key
head gasket got comp of 130/130 now!
sync & timing
thermostat & gasket (neither present before)

 

[john from md]

Re: 85 50 HP wont start

Good job! Happy boating.

John