F36 electronic ignition upgrade

[baggins]

Hi Guys,

I have a rather strange problem that i believe will end up being an ignition upgrade.

I have a 1976 F36 tri-fly and love it.

However the port engine has started doing something that no one seems to be able to fix. partly because the issue seems to be intermittent. I've now paid 4 different mechanics 5 different times to get to the bottom of it, all seem to fix the issue but then it comes back.

General description:
The Port engine some times will not start and if it does it starts well and runs very well but if i stop it after several hours of running it will not start again.

Details:
The engine is getting loads of gas, the issue is with the spark.

I had a tune up done at the start of the session (i only just bought the boat last October) both engines were running well.

during the tune up they found so much corrosion in the port distributor whilst trying to examine the mechanical advance the tabs broke of. So they rebuilt it.

It ran very well for several days (we were doing a 400 mile cruise back to home port). but then the starting issues began.

The first mechanic believed it was the coil (we replaced it). The issue seemed to be resolved but then started again later the next day.

The second mechanic believed it was the ballast resistors (we replaced it). The problem started again 2 days later.

I then found during my own trouble shooting (no mechanic around) the distributor was a little lose. I did an adhoc timing but at the same time I found the coil had been in stalled backwards (positive on negative) and corrected the situation. I also took of every connector, cleaned and reinstalled every one correctly. The problem seemed to be fixed, it ran for several days until we got home and I got a forth mechanic to do a professional timing and he reported the engine sounded great.

Went to the boat several times over the last three weeks and some times it starts really well and some times it was tough to start but i got it going. Yesterday we went and the engine will not start at all. I have not used the boat in three weeks because of the lack of confidence i have in the engine and we live on a river (landing on one engine not fun).

Any help would be deeply appreciated. The issue seems to be (from my limited experience) is week to no spark (when the engine will not start).

Two questions:

1. How to trouble shoot this further as i can not find the exact electronic ignition system on line in general trouble shooting?

2. Would it be better just to completely replace the old ignition system with a brand new and updated ignition system and if so which one ?

[mikeandanne]

I am for #2, get all the old stuff out, distributors and all.They make some very nice systems now. Now this is only the case if you are planning on keeping this boat for a while.Hope all goes well.

What engines do you have?, that will help anyone to help you further as there are a few here that have done this swap out with success.

If you have the chryslers that still have the ignition control modules, some of them were susceptible to heat after a while and would act up, much like you are seeing.

[baggins]

I do have Chryslers, they are 383. The electronic ignition may not be original but they are definitely quite old.

I have to get the info of the boat but they have a big black cover and all the components are separated on an aluminium back plate.

I definitely want to keep the boat so I'm for swapping out the part as well just not sure whats the best solution as looking on line its not obvious. and the local mechanics are younger guys that are mostly familiar with the newer engines.

[WayWeGo]

You might try putting a timing light on the #1 plug wire when the engine won't run to confirm a no spark condition. If you have one, that is a quick check that will point you in the right direction. If you get a spark and have a helper, try to verify the timing while cranking the engine. Those tests can tell you a lot about how an ignition is working.

You can also put the timing light on the other plug leads to see if all cylinders are firing, but you won't get much information on the timing without going through a lot of trouble.

Another technique to consider is swapping parts from one side to another, but if you do, make sure you look at the thrust collars on the distributors if you swap them. My understanding is that you need one on the reverse rotation engine but Chrysler installed them on both rotations for simplicity. I have heard of some people removing them on the standard rotation engine, so be careful.

[P-Dogg]

If you ....have a helper, try to verify the timing while cranking the engine.

Or a remote starter.... it's easy enough to jump the starting relay with one, then you have a free hand for the timing light.

[baggins]

Im heading to the boat tomorrow for the day so will try this out.

In the past i have popped the center lead of the distributor and barely get a spark out of the coil but will check that this is the case now as a lot has been done.

I'm still really leaning toward just buying a new ignition system as the stuff that's on there is very old and when we replaced the ballast resister is was so cooked it was black behind it and the terminals were lose. Also as i don't have access to an old school mechanic moving to a newer system has double the advantages. There just seems to be a lot of choices and i would like to move to a single (or close to it) consolidated component system and if it works do both engines.

[captainmaniac]

Just throwing this out : any chance you had a bad coil, replaced with a good coil but wired backwards so didn't work right, but even after wiring it right you still have problems because the new coil got buggered by incorrect polarization?

A couple of other things you didn't mention are wires and plugs. Are the wires old and shorting out or too resistive? Are all the plugs properly seated and are the resistor tips (that the wires connect to) tight on the plugs? I have found resistor tips and plugs that are loose in my spring commissioning checkup, which would mean possible poor electrical connection, or not developing adequate compression... wire / plug issues are conditions that could be temperature dependent. You said sometimes it runs fine for hours then messes up when you try to restart...

[baggins]

I'm just about to leave to head down there i will check what you mentioned.

For the coil, i wondered the same thing, not sure if it destroys a coil if its wired backwards as the boat ran for several days like that (not starting well of course).

I will do some swap and replace with the starboard engine today to see.

The wires looked newish when the tune up was done so the guys didn't replace them. the plugs were replaced and gaped etc. But i will pop the leads and check the resistor caps.

One think i forgot to mention is this engines burns oil i believe (about 2 litters over 400 miles). as far as i know the boat sat for two years with very little use before i picked it up so may be a bad oil ring?

Im going to go over everything today and i'll pull some plugs and take some pics.