Fuel or Ignition Issues After Warm Up

[Tranquilo]

I looked at an old thread "my 360 runs like crap.." and see a similar issue but the solution isn't the same.

Before changing the manifolds out and adding a riser, I got hydrolocked but before that happened, I would sputter and almost stall above 2200 RPM.

I changed out the manifolds, etc. I also added the new Pertronix distributor and plugs while I was at it. Took it out for a run and when opening it up to 3000, it sputtered again. I assumed the last time was due to water coming in via a failed manifold. I guess not.

I pulled into a cove and pulled the plugs: still new and shiny, no oil, dry. OK. Hung out for an hour and decided to head back. Got about 1/4 mile and she started sputtering at any speed and would die. I could get it to turn over but it would die right away.

The longer I waited, the longer it would run before dying. I CANNOT DUPLICATE THIS ISSUE AT THE DOCK. Only happens in gear.

GAS:
I'd check to see if the fuel pump was running (electric upgraded last year), it was. Saw fuel flowing through my glass fuel filter as well. I DO NOT have a fuel pressure regulator or gauge on it. I ordered a setup today. It acts like a clogged fuel line but I ran it straight from a gas can and it did the same. I seriously don't think its a fuel issue even though it "walks like a duck"

I do have gas coming out of my tail pipes when I stall. My plugs were BLACK and shiny when I got home. May just be from idling 4 hours to get back.

IGNITION:

I put a whole new distributor and plugs on this before going out. I even swapped out the coil as I was waiting (went from flamethrower to a backup accel coil) and it didn't seem to run as long before dying. So new, coil, distributor & plugs. Same thing.

I looked inside the electrical panel and found no loose or bad connections.

When I finally made it back, I pulled my alternator to have it tested (long shot but maybe its spiking or something?) but unfortunately the idiots at all of these auto part stores can't wrap their heads around how to use their testers if you didn't buy the alternator from them.

SAFETY OR SHUTOFF SWITCHES:

Are there any kill switches that I don't know about? The problem got worse after the manifolds, which run a lot hotter with the new riser setup. The block still reads 110 - 130 degrees anywhere I point the light at. My oil pressure is fine.

It sounds like a gas thing but man, it feels electrical. Even after shooting starter fluid in the carb after stalling, it doesn't turn over till it sits for a minute.

Any thoughts?

[barkleydave]

Just my gut but I have been through this drill also. Which coil are you running? What is your voltage at the coil?
You mention it does not turn over after you stop? Or it does not fire until it sits for a while? If it is not turning the engine over you may also have a engine ground issue. Also when you converted to the Pertronix you no longer use the external resistor. Sure sounds like the coil circuit may still be the fault. Also you do not mention when it dies are you losing spark? With the Pertronix I can remove the coil wire from the coil... turn it over and it still will shoot an arc all the way to the head! When it dies try removing the coil wire from the Dist. the check for spark from coil wire to ground. It should be bright blue or white. Takes two for this test.

One notet You mention you have a glass filter in your fuel system. While that is acceptable for automotive it should not be used in marine applications in engine/fuel spaces.


safe boating,
dave

[Tranquilo]

Thanks for responding

I use a flamethrower coil (the accel was my backup and it did the same thing with that installed) - read 12.5 at the coil.

The engine turns fine after stalling, just not firing up right away. Once it does fire up, it dies. The longer I sit and wait, the longer it will run before sputtering out again.

The only issue with disconnecting the coil wire for spark is that by the time I pull the wire, and get it close to the block, the thing will normally fire up within 10 - 30 seconds. It would be a mad scramble and who knows if I could trust the result.

Maybe I can set up my timing light on the coil wire and have it next to me to see what happens when I go to start it up. It it isn't flashing, I guess my ignition system is shutting down.

Would jumping the coil pos+ to my battery after it starts acting up remove any variables?

The glass filter is a pain to keep from leaking. I'll toss it in the trash as soon as I get this issue worked out!

[jralbert]

What you described in the original post classically occurs when the small filter at the mouth of the carburetor clogs. In my 1988 boat is was a CG-11 filter. I will re-read your post but I don't remember seeing any reference to changing this filter. For me, any time I tried to push the throttle over 1800 rpm, the engine would stall, coughing and wheezing. I always found it easy to uncouple the fuel lines and a bear to put them back because the angle had to be just right.

(also - I thought glass filters were verboten in inboard engines????)

[Tranquilo]

I forgot to mention that I had a little screen where the fuel line enters the carb. It was clean and I removed it entirely. Sadly, no change..

[EWRice]

First, spend the money and get a good in line spark tester. These are encased in plastic and have one or two leads coming out of either end. This will be the handiest tool you will ever own for ignition diagnosis. Put it in line with the easiest plug wire to see while driving. If you can put it in line with the coil wire, even better. Run the boat and when she starts to miss, look at the tester. It will be dead obvious weather you are loosing spark or not.

Second, how's your fuel tank vent? Sounds stupid, but I have seen it more than once.

My boat was having similar issues. Ended up being junk in the fuel tank. Plugged up filters. Then big piece of stuff plugged the pickup tube in the tank.

[Tranquilo]

I have a plug tester from harbor freight but haven't used it. The coil is the most visible while driving but I worry the coil will just smoke it within a minute or so.

I took the cap off my tank and tried to drive without the cap can't get a better vent than that. No change.

I'll look for a better one as well as a voltmeter I can leave on the coil.

[Fastjeff]

You might have a carb loaded with "White Gook" thanks to ethanol gas. It will not burn, and goes right through filters (including water separators).

Try this next time you have the problem: Shut off the gas and run the carb dead empty, pumping HELL out of the throttle as it dies out. Open the gas shut off, get her running again, and repeat. Then see if it runs better. If it does, that's the problem. Eventually you'll work your way through what's in the tank, but you may have to do the FERT (Fastjeff Ethanol Removal Technique) a few more times before the "White Gook" i's gone.

Jeff

[bobv]

I had a problem like this I had the engine running fine after a while it would not run. Both engines have pertronix distributors. had the same issue with both engines at different times. I hope its as simple for you. I pulled the cap off and is was wet inside, full of condension I just dried it off and that was all. Easy to check.
Bob

[newendeavor]

I had problems with Fuel Vents clogged by spiders.
On a side note i thought it was uncool to use Electric Fuel Pumps on Inboards ?