OMC 3.0L timing issue

[Maggot]

Recently had a used 3.0 liter engine installed in my 17" Cadorette with a 135HP Cobra outdrive. It would run smoothly at 3500-4000 RPM for 10 minutes and then would sputter and stall. I suspected the points and also the interupter switch. The easy thing was the points. Changed the points, rotor and cap but didn't touch the bottom half of the distributor. Started up on the muffs and ran fine. Took the boat out on the lake and had the same stalling issue(Interupter Switch?). Got it restated and shortly after the engine started to rap. Returned to the repair shop for warranty as the engine had less than 2 hours and was told that I may have caused the problem by changing the points. I was told when points are changed the timing needs to be reset and it was out 18 degrees. I have changed points on the water before without an issue. I feel I am getting the run around.Question what could the rapping be and could being out 18 degrees on the timing cause something bad to happen to the engine?

 

[rbezdon]

Re: OMC 3.0L timing issue

The rapping could be any one of a large number of things and definately yes, the timing being off can damage the internals of the engine. Over advanced timing causes preignition, the burning of the fuel in the chamber before the power stroke. This burning can damage (through intense heat) pistons, valves and even spark plugs. It is not a good idea to run an engine with what many auto enthusiasts call "pinging". What I am not sure of is how replacing the points, if reset properly for dwell, could change the timing that much. The only way I see it could happen is if the distributor mounting bolt were not tightened properly and I assume that was installed by the "shop" when they put in the engine. The only other thing might be if the mechanical advance is frozen in the fully advanced position and you locked it there by turning the distributor shaft during the points install. I assume you set the points by gap size which should have gotten the dwell close enough not to effect the timing by 18 degrees.

 

[tommays]

Re: OMC 3.0L timing issue

i dont see how swaping points could change the timeing 18 deg<br /><br />tommays

 

[Maggot]

Re: OMC 3.0L timing issue

The gap was set at .017 and it ran fine for a short while. I don't know if the bolt on the block was tightened properly and I'm sure they will not admit to any wrong doing. I'm into $3800 on a 1991 boat now and probably I will bail out if there is more damage that they will not warranty.

 

[Limited-Time]

Re: OMC 3.0L timing issue

As for the interupter switch thought. The ESA module is RPM governed. It has no effect over about 1500 RPM.

 

[Maggot]

Re: OMC 3.0L timing issue

It will usually stall when I back down the engine. The interupter may neeed and adjustment but I think I will replace the shift cables as they are the orginals. Thaks for the replies