Force 125 "banging" issue

Joined
Jun 15, 2010
Messages
2
I've got an 89 Force 125. I've noticed that when I apply full throttle there is quite often a "banging" almost like hitting something under the water, but it seems to be coming from the engine. Not there when I ease off a bit, but just at full power. Any ideas on what this might be? Maybe the prop or bottom end gears? Thanks
 

maxum_man

Petty Officer 2nd Class
Joined
May 2, 2010
Messages
167
Re: Force 125 "banging" issue

Check spark, compression, and timing (cranking speed at WOT). You might find something there!
 

N Wolf

Petty Officer 3rd Class
Joined
May 17, 2010
Messages
89
Re: Force 125 "banging" issue

Two things it could be.
1) timing to far advanced causing preignition or detinating.
2) Worn gears giving way under the load of WOT.
I would guess it to be number one as I doubt that a slipping gear would catch once it slipped. More likely it would break loose and grind till you lowered revs.
As for the timing, if you have the link arm installed backwards your triger coils will advance to far as you apply throtle. However they dont revers themselves so unless the problem apeared right after you had some work done you can count that out.
I would however check timing becouse the nuts on the linkage can turn on there own due to vibration.
IMPORTANT NOTE check it before you run it again as this WILL blow your motor. Check static first timing to make sure you're in the ball park (sure would suck to blow your motor while testing).
 

jaybirddog11

Petty Officer 2nd Class
Joined
Nov 30, 2009
Messages
133
Re: Force 125 "banging" issue

I was wondering if this could be a symptom of a lean condition?
 

foodfisher

Captain
Joined
Feb 18, 2009
Messages
3,756
Re: Force 125 "banging" issue

Check mounting bracket security. Push and pull on lower leg while trailered and in down position.
 
Joined
Jun 15, 2010
Messages
2
Re: Force 125 "banging" issue

Thanks. Bought a timing light and compression tester and will try out come of these ideas tomorrow.
 
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