? On Distributor Electrical Problem

[Dandydan]

I have a 302 Ford hooked up to a Volvo Penta 290 DP 1994 Sea Sport. I just recently successfully launched her after buying and installing a rebuilt long block. She ran like a top the first few times I got her out on the cold winter waters of the local lakes and sound. 3 times or so on the lake and then a couple of nice cruises on Puget Sound. Worked on getting the bugs out a little on every trip but I don’t recall any issues other than difficulties keeping it running at low speeds and having to turn up the idle and creating a scary thunk when going into gear. Then this weekend we took her out again and after idling through the long no wake zone, I proceeded to punch her up onto a plane. As the speed was building, she commenced backfiring. After readjusting the carb idle screw and the mixture jets back to what the book says is a good place to start, I tried to increase speed again and had the same backfire result.
This engine has not yet been broken in quite yet, has new plugs and wires, the carb was rebuilt by a very reputable carburetor guy, it has new fuel pump, and sea foam treated non ethanol gasoline. The intake manifold was machined when I put the whole thing back together. Like I said, it ran like a top until this week when something went awry.
My question is whether or not should be suspecting a electronic issue or fuel problem. I did not replace the distributor when I put the motor back together and would like opinions on HEI distributors and whether it would work on this motor. The current distributor is the type that has done away with breaker points, but I’m not sure I understand the HEI thing. Can you give me some insight?

 

[Dandydan]

So I am shaking my head. My dad always said most misses are caused by electrical issues and not the carb. He never did have a boat though. Seems he was right again though. Found my trouble right away I think. The # 8 plug wire had come off and that sure would cause a miss/backfire under a load. Can’t believe i didn’t catch that while out on the water. Anyway I still wonder why I can’t seem to get the idle right. There is a disconcerting clunk when going from neutral to forward or reverse because she wants to idle about 1000 to 1100 rpm and slower than that she dies. Carburator or electrical? Like my dad says? Probably electrical? What do you think?

 

[Scott Danforth]

if you are clunking going into gear with a 290, you are either low on oil and have destroyed the cone clutches or you have an improperly adjusted shift cable.

a bad dizzy cap will also cause backfiring.

HEI is a GM trademark name for ignition. it is also used under license by Davis Unified Ignition.

if you have the original dizzy for a 1994, it should be a prestolite electronic. Volvo quit using points on V engines in the early 80's

 

[Bondo]

Worked on getting the bugs out a little on every trip but I don’t recall any issues other than difficulties keeping it running at low speeds and having to turn up the idle and creating a scary thunk when going into gear. Then this weekend we took her out again and after idling through the long no wake zone, I proceeded to punch her up onto a plane. As the speed was building, she commenced backfiring. After readjusting the carb idle screw and the mixture jets back to what the book says is a good place to start, I tried to increase speed again and had the same backfire result.

Ayuh,..... Welcome Aboard,...... Sure sounds like a Carb problem to me, or atleast a fuel delivery issue,......

I'd start by checking the contents of the fuel filter, for anything but clean fresh gasoline,.....