Coil failing ??

[Quadruplecccc]

Ok , I've posted about not being able to get to WOT. Thought I had a timing problem caused by a beefed up cam. Have been setting up the timing as per clymer book @ 10* btdc. Takes all the rpms I can give it in the drive way. Put her in the water and get her up to 3000rpms or so and then it will start to buck a liittle and stall if I don't pull back on the throttle in time
When ths first happened I was running a 2bbl Holley 2300 and thought maybe I was under carbed.
Switched to a Holley 4160 4 bbl and had the same results ,( maybe a tad worse )..
Been adj. timing a litle this way and a little that way, wiich makes it run not as good and keep coming back to where I started.
So, it's not the carbs cause I get the same results from both, and now I want to rule out the timing. Was sittin here thinkin about it and began to wonder if my old coil could be cuttin out around the same load draw
Can this really happen??
Motor is a 76' 351 windsor 233hp (overhauled) mercruiser.
Please help I'm stuck!

 

[Lyle29464]

Re: Coil failing ??

I think I would run a compression test to make sure your not off a tooth on the cam. while your doing the test look to see if you have 2 plugs that dont look right. Ford used several firing orders back then and it is not unusual for the firing order on the intake to be incorrect for your mods.

 

[Quadruplecccc]

Re: Coil failing ??

Will be starting all over, checking comp, timing and all. I can only find one firing order for that year motor and have all the wires correct. Also have new plugs,wires,cap,rotor on already.
Wouldn't I notice a compression proplem running motor in driveway??. Doesn't miss or anything noticeable when idling or revving up.

 

[Lyle29464]

Re: Coil failing ??

a weak fuel pump or a restriction in the fuel flow will not effect the motor with out a load on it. Same thing with the ignition. you need the load to bring out the problem. you can adjust the timing underway and elimate that as a problem. 2 wires crossed will have a different effect on different engines. The compression could be off a lot and still run well under no load. you can test the firing order by grounding the plugs one at a time. if you find 2 that are not doing anything cross them.

 

[Quadruplecccc]

Re: Coil failing ??

Are we saying that the coil is not the problem here???

 

[6meter]

Re: Coil failing ??

Coils are cheap. Replace it. Atleast you will know that it wasn't or it was the problem.

 

[Quadruplecccc]

Re: Coil failing ??

May have made a mistake dropping the distributer in. It was set at 14* timing mark on harmonic balancer instead of zero.Rotor was pointing to #1 plug wire. Will this cause all this grief at WOT.
So if I set timing to 10* btdc on top of that what would the motor do.? Hopefully I'm going the right direction with this.

 

[lonemust]

Re: Coil failing ??

May have made a mistake dropping the distributer in. It was set at 14* timing mark on harmonic balancer instead of zero.Rotor was pointing to #1 plug wire. Will this cause all this grief at WOT.
So if I set timing to 10* btdc on top of that what would the motor do.? Hopefully I'm going the right direction with this.

The balancer set at 14* when you stabbed the dist in. Then you started the engine and set the timing to 10* btdc, that would put your timimg at roughly 4* atdc. You need to pull dist and restab it with the balancer on 0*(tdc) after that set the timing(with a light) to 10* btdc. How well that works.

Make sure #1 cyl is on tdc compression stroke when you do it. Even with the bigger cam you still set the timing like it is a stock cam. The advancement of the cam is done at the timing chain not the distributer.

 

[Quadruplecccc]

Re: Coil failing ??

Thanx FINALLY all this input seems to be going inthe right direction. Restabbed the dist.earlier as this is what I thought would be the next logical step.
Motor still revs up great as it did before but the biggest change is that she starts with ease now instead of lugging the starter.
I'm heading out to the lake rightnow to give it another go. 20mi each direction so it'll take some time to report back.

 

[Quadruplecccc]

Re: Coil failing ??

ok. just got back from lake. Started great as usual and set out to see what results I could get. Engine up to full temp and off we go.
RPMs climbed to 3k and all was lookin good. Told my son to let er rip and blah she stumbled again.
This time I was prepared to swap primary bowls on the carb to one that I can adjust.

After a couple of adjustments we were off again. Up to 3k then 3.2k --3.4 all the way up to 3700rpms. WOW what a change! Got about 34mph at 3700rpms by gps.
ran around for along time enjoying the ride and decided to head for home.

Idled in and all of a sudden she starts to run like crap. Popped air cleaner offf to have a look and found that the secondary bowl is now letting fuel flow in , basically flooding her out.
More adjustments needed but if it wouldn't be for that she was running great!.

At least now I'm headed in the right direction.