360 Chrysler running like crap cont...

[bill]

Follow up from last fall.

Went to Put in Bay Ohio last week end. First trip of the year.
70 mile round trip. Averaged about 15 mph at a little under a gallon a mile.
Crew of seven men and gear with beer , full fuel tanks 250 gallons and 20 gallons fresh water.
She purred like a kitten.
Thanks again Ron Spies for finding the problem with the caps and all the carb adjustments..
bill

[bill]

Its back with a vengeance.
Headed to the Bay at 2900 rpm, about 90 minutes out starboard engine starts to fall off on rpm. Finally stalling out. Continued on for awhile, while first mate took over the helm I went down and replaced water/fuel separator and filter at carb. Starrboard engine started back up but would not allow me to put it in gear. Kept stalling.
Decided to turn around and head for home with one engine. Just before entering creek where boat is kept I fired up the port engine and when I put it in forward it stayed running. But mr. starboard said no way and stalled. So here I am driving this 37' in a narrow creek with one engine. So far I have checked the fuel tank vent for blockage and they were clear. Checked fuel from old filters for water or debris but the fuel was clean. I am using 90 octane marine/ rec fuel --no ethanol. Plugs pulled and appear to be burning correctly, Wires are two years old, new caps and rotors last year. Did the fastjeff flick on the distributors to check the centrifugal advance springs Replaced ECM and ballast resistors. Also replaced the pickup coils in the distributors and checked the reluctor to pick up coils spacing. I have a pressure gauge installed just before the carb, showes 6 psi while running. Ran at dock for two hours, No problem
Anyone have a idea

[bobv]

I had a similar problem when i was running the original distributors. it turned out I used the wrong rotors They make two different ones for the small block Chrysler. The fit was verry close it turned out the rotor was hitting the cap. When the engines warmed up they would stall ,sometimes would start up and sometimes not. After inspecting the rotors I realized they were cracked .After installing the correct ones there was no more issue.
Hope it is that simple . Good luck
Bob

[DougDoty]

You have diligently worked through a lot on this deal but don't forget to step back a little and remember it is just Fuel air and spark. Maybe a quick coil and or ignition module swap real time while it is malfunctioning. Shut it Down put a buddy on the helm and jump in there while under way and do the swap. You could do both in 5 minutes or so, or maybe one at a time for better diagnostic feedback if so desired. I do not like making two changes at once as I question what the fix was, even when things go well. It really does sound like ignition breakdown from heat and time if the fuel pressure for sure !! holds solid !! so an IR gun to monitor the temperature of the module and coil as you run might be interesting. Worst part of parts swapping is that so much of this crap like coils and ign. modules are coming from China these days and we trust them because they are new but can be so substandard compared to the good old OEM parts. You already know this since the Dist. cap ordeal !!! I would even keep my timing light handy to peek at it as it starts to falter. I am all over the ignition side of things since you have installed fuel pressure gauges and I am sure you are monitoring that and you are not likely loosing available air to the carbs !! .... Leaves "spark" or in the bigger picture ignition somewhere as the culprit and I still bet on the coil or box.

Seems extremely unlikely but there is target test ohm reading per. linear/foot for plug wires and they would surely test more poorly after heat soaking, but that is pretty far out there and I have never sen it, I just remember reading back in the thread where you added new Napa plug wires so they are on the radar.

I am not wanting to sound like a Chrysler tech cause I am not but I did drag race and tune carbureted Chevrolets and Small Fords for nearly 30 years so I am pretty solid on engines and making them run with that experience.

I have the potting compound running out the bottom of my ignition boxes right now but no running issues from idle to WOT so I am going ahead and trading them out as it is a great time to test new parts when everything else is working right. I fear I am opening a pandoras box for the future. I distrust the new modules so bad I have 2 additional random new spares beyond the new ones I ordered and will not toss the old ones completely out for a while until things prove to be ok. I am kind of ok with the stock chrysler ignition stuff cause I kind of like stockish stuff but about one good gremlin like yours and I'd pitch it all for a better modern alternative.

[EWRice]

I know that there are so many different components that can cause these problems. Intermittent issues are the worst to diagnose, and many owners AND technicians will start to change parts to find the problem. Sometimes it works, sometimes it doesnt. Sometimes it will temporarily mask the real problem until a replaced part fails again. This is especially true with electrical, and more specifically ignition problems. I have seen so many times where there is high resistance in ignition circuits in the dash that cause strange driveability issues. You would not believe how many times I have repaired loose wires on ignition switches, or corroded terminals that heat up under load. Voltage drop tests are always more accurate than checking for power at the resistor, coil or module.

Also, more than once I have seen a tach have internal shorts and make the ignition system go nuts. If all else fails, disconnect your gray tach wire and run it.

Be patient, don't change too much at once, and keep notes.

[DougDoty]

I know that there are so many different components that can cause these problems. Intermittent issues are the worst to diagnose, and many owners AND technicians will start to change parts to find the problem. Sometimes it works, sometimes it doesnt. Sometimes it will temporarily mask the real problem until a replaced part fails again. This is especially true with electrical, and more specifically ignition problems. I have seen so many times where there is high resistance in ignition circuits in the dash that cause strange driveability issues. You would not believe how many times I have repaired loose wires on ignition switches, or corroded terminals that heat up under load. Voltage drop tests are always more accurate than checking for power at the resistor, coil or module.

Also, more than once I have seen a tach have internal shorts and make the ignition system go nuts. If all else fails, disconnect your gray tach wire and run it.

Be patient, don't change too much at once, and keep notes.

Very good points !!! I would add that I was working in the boat barn last week and our biggest possible 110v air compressor quit starting on demand and shut us down. I brought it back to the marina for some evening dock diagnosis and the issue was an over heated wire at a crimp connector where it plugged into the pressure switch. Easy fix but was a hard to find tired little piece of wire. I had seen it for some time but today it looked the same and give up.

One other odd deal and I forgot where it came from but not my original idea ... I remember reading a while back about a guy chasing some kind of an intermittent problem but do not remember many details but here is the punch line. He said was getting water past the separators somehow when running bow up and realized it from pulling and flipping his carb and draining it in a container and he had a separated blend of water and gas !! I just committed to remembering this cause it was unique and a lot of boats unfortunately get a bit of water in their fuel tanks. Put it bow up and that float line can change levels relative to the pickup. He even commented that he trusted his fuel quality to the carb since his genny ran great out of the same tank but later realized it would due to the shallower pickup.

We had a good mechanic and boater at our marina found some water floating in the bottom of his tanks while replacing his pickups in the last month and he had sufficient access to see it through an inspection port and draw it out of the lowest point until non existent. He had a pickup that was just wrong and was drawing off the very bottom of one of his two tanks and he could run about 2 miles and his port engine would die like yours. So pitch fuel quality at the carb into the list of possible things to look into as well. Fuel air spark, air rarely leaves other than in you choke deal !!, fuel present is easy to verify and maybe actual quality of fuel into the carb might be another drill down step.

[Tranquilo]

Just had this problem. Not sure if its fixed completely because its only been out a few times last weekend.

What I did was load up on spares and long jumper wires and go out so I could troubleshoot while it was happening.

FUEL SYSTEM
After installing a Fuel Pressure Reg, I saw my fuel pressure would drop to 3psi IF I accelerated. You NEED to watch the gage as it stalls. I rerouted the fuel lines so it was as short as possible and it acted much nicer. (cut out about 10 feet) Still think my electronic fuel pump is weak so I have a spare.

I dumped a bunch of Tachron in my carb, tank and fuel sep the night before I went back out. My carb is 6 months old.

IGNITION SYSTEM
Because I don't believe in ghosts, I added a ground wire directly to the distributor body. Not sure if it was a problem but I read power at the coil and a coil swap made no difference. That lead me to believe it could be a ground issue because my ground terminals are corroded as hell.

My distributor was replaced with a new Pertronix unit. Problem remained until it magically disappeared

I had my timing light hooked up to the coil wire so I could see if we lost spark when it sputtered. Once connected, the ghost went into hiding and I never got the chance to use it. If you have voltage to the coil and the timing light stays pretty much on when lugging out, its a fuel thing.

I also made a jumper wire to my battery in case I was dropping voltage. My tach is disconnected to remove that part and if power was getting cut, I was going to jump to the battery and see if that made a difference. If it did, I'd check the panel wiring.


I don't believe it's totally gone on my end but I can't be sure until it happens again. I'm as ready as I can be right now for a holiday weekend let down.
Get out there and enjoy the wonderful world of boating

[railrunner04]

Damn...... I was hoping for that smoking gun for you Bill.
Was thinking about your ignition switches might be worth just havind a look at the wiring behind the dash i suspect a lot of the problems my dad was having with stalling were coming directly from there but then again who knows im pullin for ya though give us a call if you need a hand or a few cold one's on us

[Fastjeff]

Hate to say it, but problems like that ALWAYS return. At least you'll be ready for it.

Good luck.

Jeff

[Tranquilo]

That was the time I hoped Jeff would disagree