engine won't start

[parnold]

trying to save some time trouble shooting. took a 6hp johnson that hadn't started in a while. put engine cleaner in gas, sea foamed it, changed gas tank, cleaned fuel pump, new plugs, made sure oil in cylinder, compression check was fine. replaced impellor to be safe started and ran well in tank. worked fine for a month. last time out (ran fine the day before) started sounding tinny and lost power. shut it off and brought it home to check it out. plugs a little fouled but not bad. changed them out didn't start. spark blue but wasn't even acting like it would fire. put mixture in cylinders still wouldn't fire. any ideas?

 

[crxess]

Re: engine won't start

Recheck compression. Sounds like the head gasket failed.

 

[JB]

Re: engine won't start

Go do "Outboard won't start" in the Engine FAQs Forum.

Let us know what you find. I am thinking a sheared flywheel key.

 

[parnold]

Re: engine won't start

jb already checked out yours and tashasdaddy posts (+ a 100 others), which by the way are great help for a newbie but the compression is dead in both cylinders. I checked this morning after reading crxess post. any other seal that can cause this? also thought of the flywell key, leaf vlaves and even a leak at the packing nut but don't know if any of those would prevent pressure in the cylinders. was hoping for something simple but not looking good

 

[tx1961whaler]

Re: engine won't start

Take off the head, inspect the cylinder walls for scoring. If OK, then install a new head gasket and torque it down properly. Re-torque after first run.
Did the motor overheat?

 

[crxess]

Re: engine won't start

Head gasket is fairly simple. 7 bolts. Just orderd a replacement to change my head today. $15 shipped.

Once you have the head off you can inspect the cylinder walls, Piston play, Head surface condition.
If it ran hot the head can be warped. It can be sanded flat on a good flat surface like a glass pane with 120 wet/dry paper in a figure 8 motion.

One suggestion: after pulling head. Tilt motor cylinders up. turn until pistons are equal in cylinders. Poor in some PB Blast and let it sit over night. It will free up stuck rings and/or let you see now fast fluid passes the rings.

 

[parnold]

Re: engine won't start

didn't overheat as best as I know. only changed the impellor as a precaution after reading some posts. before and after in tub was like bathwater. can't be anything in the carb etc?

 

[parnold]

Re: engine won't start

where did you order from? 1967 6hp, some parts are different from the 68

 

[crxess]

Re: engine won't start

Local small shop ordered for me.
iboats can send it to you. Part is Sierra branded 18-2961 fits 1965-1979

 

[parnold]

Re: engine won't start

thanks

 

[parnold]

Re: engine won't start

how long do you leave that pb blast in? it's gone down a little after about 45 min

 

[parnold]

Re: engine won't start

just finished and it started. since I had it down I rebuilt carb, changed points and condenser, replaced flywheel key although the old one looked good, replaced head gasket and pulled motor to check the bottom seal that was OK. Cylinder walls looked OK but no idea if the rings were good. had to squirt solution in carb to get started. Minor problem the idle wasn't steady. Would idle OK for a few minutes and then would speed up for maybe a 1/2 minute. Didn't over race but it was noticeable. Not sure if I did the low speed right or if it could be something else, any ideas.

 

[parnold]

Re: engine won't start

just finished and it started. since I had it down I rebuilt carb, changed points and condenser, replaced flywheel key although the old one looked good, replaced head gasket and pulled motor to check the bottom seal that was OK. Cylinder walls looked OK but no idea if the rings were good. had to squirt solution in carb to get started. Minor problem the idle wasn't steady. Would idle OK for a few minutes and then would speed up for maybe a 1/2 minute. Didn't over race but it was noticeable. Not sure if I did the low speed right or if it could be something else, any ideas.