omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

[bruceb58]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Picture stolen from DonS

 

[Jd 1978]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Thanks mzahn and bruceb58 for the timing help........Finally was able to get back to work on the boat. Got the timing all done, set it at ten advanced like the distributor kit said with the timing shunt installed. Motor starts and purrs ! Timing is my first question. After i set it and pulled the shunt tool I decided to recheck the timing and it was way advanced. I dont have a advancing light to see where it waa at but is this normal ? My guess is this is normal........next I wired in the shift assist wires and that went pretty smooth. Which brings me to another question, the motor doesnt interupt when going from neutral to drive or rerverse. I know the kit I put in works because I can manually depress the switch and the motor stumbles like it should. So I went through the adjustments in the manual and t still doesnt stumble the motor. Guess thats a this weekend project. Any pointers on adjusting the linkage ? And the last question the distributor kit came with plug wires but I already had new ones on my motor. Any difference between auto and marine on plug wires ? Thanks for the help it is much appreciated !!

 

[Jd 1978]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

I hope I am correct to continue posting in this thread? I know some time has passed in between posts but i think I read that original thread author was able to? I hope so. .......I have had the boat out several times since upgrading the ignition and the boat runs and idles very good. Here is the biggest problem now, the top speed is way low with the new ignition set up. Before with the old setup ( the automotive distributor and the factory points) the boat would hit around 43 44 mph at 4300 rpm. with the new marine setup the boat can only pull around 3400 rpm at 33 mph. Is this normal ? the last time out on the lake i decided to advance the timing (unknown amount of advanced timing) and the boat got faster and faster everytime i moved the distributor. I reached the 43 4300 rpm by advancing the timing and there seemed no ill effects by doing so ( no pinging or detonating could be heard)but the boat was hard to start so I knew I have to much timing now. Anybody know a fix for something like this ? Im pretty sure I have everything hooked up correctly, the wiring in the distributor kit is a no brainer.Any suggestions ? hotter plugs maybe ? thanks for the help!

 

[Jd 1978]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Anybody out there ??!!

 

[bruceb58]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

I can't believe you are trying to set this up without a timing light.

 

[LAC_STS]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Yea I would like to know how you thought setting/adjusting the timing without a timing gun.

 

[Jd 1978]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Guess I am guilty of playing with the timing at the end of my last outing. But the initial or base timing was set with a timing light and the shunt tool installed. Ten degrees is where input the base timing. But like I said the boat is so much slower now and the only thing that has changed is the ignition components. I know playing with timing is fretted on but didn't think I would hurt it any especially when I was listening closely to noises. But back to the question, why would performance suffer so much ??!!

 

[bruceb58]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

If the distributor wasn't advancing properly.

You took the shunt off right. Get your timing light and measure total advance. If you don't have an advance type timing light, get some timing tape and put it on the harmonic balancer and measure what your total advance is.

 

[Jd 1978]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Yes bruceb58 I removed the shunt tool. The port on the distributor that the shunt plugs into is also where the shift interrupt wires plug in.... I have used an advancing timing light on it and if I was using it correctly at 3000 rpm the advance was reading 30 degrees. Here is what I was doing, I hit the buttons on the timing gun until the timing mark went to zero and then read the degrees on the display. Sound right ?? Boat runs and rides good. Just lacking rpms to get it moving faster.

 

[bruceb58]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Yes, you measured it correctly.

Sounds like you are getting more advance than the stock distributor has at 3000RPM. Maybe its coming in early. The stock distributor has 20? advance so total advance is supposed to be 30? with the stock one assuming base is at 10?. Would be interesting to measure what it is at 4000RPM just as a check.

Sounds like something else happened and its not your distributor. I certainly wouldn't be messing with adding more advance than what you already have. Just because you aren't hearing the ping now doesn't mean it isn't happening or you won't have it under load.

 

[Jd 1978]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

I guess I'll try and rule the distributor out. This Saturday I'm gonna double check that base timing is at ten degrees. Then run the rpms up and record at 2 3 and 4000 to see the advance and what it's actually doing. Can this be done accurately out of the water ? That's where I got the 30 advance reading from. It's really hard to do it on the water cause you have to relocate the battery and remove the tray to even look at the balancer.

 

[bruceb58]

Re: omc cobra 5.0 interuptor switch doesnt work after upgrading ignition ....

Can this be done accurately out of the water ?

Of course it can. Distributor has no idea if you are in the water or not. It just spins.