Compression release mariner 25 hp

" 25 hp mariner 1995

When c

" 25 hp mariner 1995

When cranking motor with pull chord i get a hard catch about every third or so pull. It's so hard that if your not ready for it, it will pull the chord out of your hand and hurt like %*##. Also when starting with starter I hear the motor knock hard about every 10th revolution. Is there a compression release on this motor and could that be going bad? What could this be? "

" Greg,

It sounds like a pi

" Greg,

It sounds like a piston is hitting the counterweight on the crank. This is caused by a badly worn bearing.

Tony "

" is there a way to for sure d

" is there a way to for sure diagnose this on my on.
should i get this fixed or wait til it dies? will it cause more damage if i wait?

Also, another message board said this may be a "lean sneeze" and to back out the mixture screw. Does that make sense?

thanks. "

" Greg,

If the piston is hi

" Greg,

If the piston is hitting the crank, it will get worse and destroy the engine, but if the damage has not gone too far, it can be repaired. It may be fairly expensive, even if you do the job yourself.

You should be able to remove the spark plugs and insert a wooden dowel ( or some other probe ) through the spark plug hole. Push against the piston as you turn the flywheel. You should be able to feel some binding if contact is being made. You should also be able to detect the play in the worn part this way.

Tony "

thanks tony..
I've not d

thanks tony..
I've not done this yet but i will add that while i was diagnosing a previouse problem i turned the engine over a good bit with the plugs out and i did not notice any catching or binding while doing that.

I'll try your test and let you know.

thanks again.

i did the test with the wood

i did the test with the wood dowel and did not notice any binding or slack in the piston. When i'd shake or wiggle the flywheel i could hear a slight rattle. Is some rattle normal?

there is some shake or miss in the engine at an idle but from idle up to wot it's as smooth as silk.

what do you think?

" Greg,

You should not noti

" Greg,

You should not notice any rattle when moving the flywheel.

Maybe the lever lock on the manual starter is not adjusted properly and is causing the recoil mechanism to lock up. Have you checked this yet? The purpose of this part is to prevent starting in gear.

Tony "

thanks for your help tony but

thanks for your help tony but i had to give up and take it to the shop. should know in two weeks.
I really think it is a fuel/carb or timing problem.
if i cut the kill switch where it does not get fire then the motor spins and pulls fine with no catches. it's only when the plugs are firing that it catches so some how or another i think its firing too quick. it is also hard to get cranked.
thanks again for your help. i'll let you know.