Engine very hard to start after cleaning distributor advance mechanism

[TomG]

Well, today was to be the day when I ran the engine long enough to confirm the new standpipe corrected my problem of water entering the carb from the exhaust manifold.

Alas.

After getting to the boat, I checked the fuel tank and the carb fuel bowl for water. All was good; no water or separation. Engine fired up after a fuel seconds (the fuel pump had to refill the carb fuel bowl). Ran at idle nice and smooth for few minutes and the residual MMO burned off. Once the engine was warm, I gave it a little throttle and it didn't want to accelerate. Everything else seemed fine - water temp, oil pressure, sound, etc. It seemed like the timing didn't want to advance so I shut her down, popped the disty cap and pulled the plate with my petronix EI module. Sure enough (and somewhat surprisingly) the flyweight advance mechanism had a fair amount of rust and gunk on it. I took it completely apart, took a little emery cloth and cleaned off the rust, sprayed a little T-9 (anti-rust/lube) on the pieces and reassembled the advance.

Congratulating myself on a job well-done, I tried to start. No bueno. Hmmmm. Throttle off the stop, full choke, nada. Hmmm. Throttle off the stop, no choke, no joy. Try a couple of iterations. Finally, with no choke and what would normally be 3/4 throttle, she came to life, but really sounded awful... like she was lugging at 900 rpm. She wouldn't take any more throttle or any less. Hmmmm... must be the main jet got clogged after the new fuel went in and something settled down in the jet once I stopped the engine to check the advance mechanism.

Congratulating myself on my keen troubleshooting skills, I removed, drained, and thoroughly cleaned all the ports and passages in the carb. The good news was, everything looked good inside the mighty Zenith. Reassmebled and reinstalled the carb. Not good. Same as before. Hmmm. Must be something in the disty!

Congratualting myself yet again for superior troubleshooting and courage under fire, I took a long, close look at the whole enchalada. Cap looks fine, rotor looks fine, and the advance mechanism seems smooth.

Re-tracing my steps, it seems strange that it go from running smoothly at idle (but not taking additional throttle) to barely running at all. She has never run this poorly since I've had her.

Questions I have:

1. Could removing the petronix EI module cause these symptoms? I would think that the EI would either work or not... not in between.

2. Could a bad coil cause these symptoms?

3. Could I have inadvertently damaged the EI, the coil, or the disty by my gentle and straightforward machinations?

4. Any recommendations on what to check next?

Thanks in advance,

[hanleyclifford]

Check timing. When you fixed the centrifugal advance you may have retarted the timing because the weights had been stuck in the advance position. Reset initial timing to TDC.

[ndutton]

I'd also check everything distributor related as long as you're there. Look for pinched or otherwise damaged EI wires, distributor cap seated properly, etc.

It ran before you got into the distributor and not after so that's where to look. If the advance weights didn't work before and now they do, there's a change (timing change as Hanley stated). If the cap was seated properly before and now it's not, another change. If the EI wires were intact before and inadvertently damaged in this exercise, change again. Did you remove or otherwise manipulate the plug wires? How old are they? Did you remove the distributor or make repairs in place?

Don't forget the usual scenario around here, multiple issues. I've got to believe it's related to the distributor repair somehow though.

[TomG]

Hanley,

I'll try that. It's hard to figure how the timing get off since I never moved the distributor, but stranger things have happened. Thanks.

Neil,

Access to my engine is nothing short of wonderful, so getting at things is rather painless. As such, I simply removed the distributor cap with the leads still in place. The leads looks good and are original to the 2008 MMI rebuild. The switch was off, and I was very easy on the EI module. I didn't even have to loosen the disty, much less remove it, so I doubt there is much mischief at play there. The one thing that has me scratching my head is the magnetic ring for the EI. Maybe I'm just grasping at straws, but it feels like there is a little "slop" when the mag ring seats on the flats of the shaft. If that's the case, it would be enough to throw the timing off. That just seems so far-fetched...

The advance mechanism is a very simple critter and I didn't have any leftover parts when I was finished. I was surprised at the amount of rust inside. Here is a picture prior to cleaning:



I do agree that the smoking gun is the distributor work. I was just hoping I was missing something obvious...

[Marian Claire]

I remember having to push fairly hard to get the mag ring to seat properly. When it did seat there was no slop. Dan S/V Marian Claire

[ndutton]

Can you report that although rusty the weights still moved freely before you spruced things up? If so I think any concern over a change in timing due to the advance mechanism is off the table.

As far as the distributor work, it leaves an improperly seated cap as a possibility. I mentioned it because I've found I have to be careful when installing to be sure it's down where it belongs.

But don't assume anything. Check and double check. What harm can come from insuring the timing is correct? And the cap? It might be time to start checking the spark at the plugs.

As for the magnetic ring, mine's pretty snug. Has yours always been sloppy?

[Dave Neptune]

2 things

Tom, when you found the advance mechanism stuck, were the weights out in the open position or in the closed position and/or were they stuck or just sticky? This could have a bearing on your timing position.
Second, when you remover the "plate" that holds the EI did you remove the EI? A tiny change in position there can go a long way.
Can you get close to TDC by rotating your engine? If so you don't really need a light just a way to observe the spark.
If it ran before and all you did was free up the advance, we can guess which way it is off. The advance can make a differance of over 30 degrees.
If you did not change the wires they don't change them selves for fun!
This has to just be a simple timing problem.

Dave Neptune

[TomG]

Can you report that although rusty the weights still moved freely before you spruced things up? If so I think any concern over a change in timing due to the advance mechanism is off the table.

Hard to tell. The advance would move, but I wouldn't say "freely".

As far as the distributor work, it leaves an improperly seated cap as a possibility. I mentioned it because I've found I have to be careful when installing to be sure it's down where it belongs.

I agree. I even suspected a bad rotor cap, but I don't see any tell-tale signs. On my engine (not sure about all the varieties), the rotor cap is secured by two screws. These line up without problem.

But don't assume anything. Check and double check. What harm can come from insuring the timing is correct? And the cap? It might be time to start checking the spark at the plugs.

Well, I'm getting some spark, because I can get it to run, albeit very poorly. My troubleshooting efforts had to end when I ran out of time last night. In addition to all the other hijinks, my water pump is leaking and needs to be repaired before I can run the engine again.

As for the magnetic ring, mine's pretty snug. Has yours always been sloppy?

Dunno. This is the first time I've had to remove it since I got the boat.

Thanks for the suggestions, Neil. I really do appreciate it.

[msmith10]

The ring should definitely not be a sloppy fit. In fact, the main danger with installing the ring is that it's such a tight fit it's easy to break when you put it on if you use too much force.

[TomG]

Tom, when you found the advance mechanism stuck, were the weights out in the open position or in the closed position and/or were they stuck or just sticky?

They were as you see them in the photo above. Closed. They would move with a little "persuasion", but they definitely needed to be cleaned and lubed.

This could have a bearing on your timing position.
Second, when you remover the "plate" that holds the EI did you remove the EI? A tiny change in position there can go a long way.

I didn't have to remove the EI module. I just removed the plate.

Can you get close to TDC by rotating your engine? If so you don't really need a light just a way to observe the spark.

Yes, I can get to TDC. I just ran out of time last night and had to work this weekend so I thought I'd run my problem by you guys.

If it ran before and all you did was free up the advance, we can guess which way it is off. The advance can make a differance of over 30 degrees.
If you did not change the wires they don't change them selves for fun!
This has to just be a simple timing problem.

Dave Neptune

Dave, I hope it is just a simple timing issue. Thanks for your help.

[TomG]

The ring should definitely not be a sloppy fit. In fact, the main danger with installing the ring is that it's such a tight fit it's easy to break when you put it on if you use too much force.

Mark, Thanks. This is what I'm thinking might be the culprit. I'll call Ken on Monday and see what he says.