Engine won't start right after a shutdown

[krazzz]

I bought my boat this year and it hadn't seen water in over 14 years. After spending many weekends on the my motor it is now starting and running like a top. My problem now is that it doesn't want to restart after I shut it down. It doesn't seem to make a difference if it was run for only on for 2 min or two hours. If I wait 5 min it will fire up without hesitation. If I don't wait it cranks and cranks but doesn't want to fire. It is strange but if I put the choke on it at least acts like it wants to fire and will sputter a bit before dying. But, if I wait 5 min, it fires up normally. I just can't put my finger on it. It starts, runs and idles so well. My only problem is the hot start.

Here are the things I have done to it this summer:
Oil Change
Drained old fuel
Spark Plugs
Plug wires
Cap & rotor
Electronic Ignition
New Flamethrower Coil
Disassembled and cleaned carb
Added a water separating filter
New fuel hose
Two new batteries


Edit: I recenly read that using the electronic ignition and flamethrower coil the spark plug gap should be increased. I am at .035 right now and read that I should go to .045. What say you?

[hanleyclifford]

You may have a fuel starvation issue. Check float level in the carb and at the same time check the main jet for partial/intermittent blockage. Be sure your choke is actually closing when you pull the cable; sometimes linkage needs to be adjusted.

[JOHN COOKSON]

Once you're sure the carburetor\fuel system is correct if you still have a hot no start issue try running a wire from the big terminal on back of the starter motor to coil +, which will bypass the boat's wiring, and try to start the engine. Do not leave this wire connected and hot for more than a minute or so or you will fry the coil.

Also the coil may be overheating. Is there enough resistance in the new coil to handle the increased dwell time from the electronic ignition? There is intreplay between alternator output voltage, coil resistance, and dwell time. Sometimes it is necessary to add an external resistor to balance all the factors involved. (Neil: Are you logged on?)

TRUE GRIT

[Dave Neptune]

krazz, how do the plugs look? Sooty, oily or clean?

Dave Neptune

[ndutton]

Also the coil may be overheating. Is there enough resistance in the new coil to handle the increased dwell time from the electronic ignition? There is interplay between alternator output voltage, coil resistance, and dwell time. Sometimes it is necessary to add an external resistor to balance all the factors involved. (Neil: Are you logged on?)

Yeah, just passing through. You have it covered well, no need for me to repeat except to provide a link for more detail.

http://www.moyermarine.com/forums/showthread.php?t=5845

[krazzz]

The coil came with ignition as kit so I assumed it was correct but haven't actually checked it. I does feel hot but it is also mounted right to the block and near the exhaust so I would have been surprised if it wasn't hot. Plus I have the same problem even if it has only run for a couple minutes.

The carb should be good. I went through it all early on because I was having fuel problems. It was completely disassembled and is squeaky clean now. It also has a brand new Racor filter/water separator. It runs smooth under power and idles well at the dock. It also starts in an instant when cold or at least sitting for a few minutes.

The plugs only have a few hours on them buy they are clean and dry.

Like most engines, I should not have to choke it when warm, correct?

I do have some concerns about my alternator and that is the next item on my list. When I got it the heavy orange wire was disconnected don't know why.) I hooked it back up. I have shore power so my batteries (which are new) are always topped off. When running it doesn't seem to be putting out much juice but then again the batteries should be topped off so not much is needed. I haven't spent any time on it as there have been more important issues that needed addressing. It is next on my list though. I don't do much motoring and have shore power so I don't rely on the alternator and would probably be fine if I didn't have an alternator at all. I just day sail and only need the motor to get in and out of the harbor which takes at most 20 min.

[Dave Neptune]

Normal

krazz, I always have to choke my engine hot or cold, mostly because I have the idle as lean as it will run the way I like it .
When warm it will restart just after I shut it off but more than a few minutes sitting and the choke is a necessity for a quick restart.
It is very common to require the choke for warm starting with an updraft style carb. The updraft type carb has no acceleration pump as does a down draft so you can't just crack the throttle and get a squirt of gas for instant starts~~normal.

Dave Neptune

[yeahjohn]

My typical restart procedure after sailing is to, attempt to start the engine first without choke, then if it doesn't go on the first turn of the key, I choke it and start it right up. I run a little rich because my engine in its current state seems to like to run on the rich side. It is easy to replace both coil and fuel pump. I have had both go out on me and both will let the engine occasionally run only to fail you every so often when they are slowly dieing. You could also just be running to rich.

-Fuel pump
-Coil
-Carb (adjust mixture to 3/4 turns or more 1 1/2 is a good spot)

[JOHN COOKSON]

The only thing one can say for sure about a heat damaged coil is that the damage is progressive.
Otherwise they can act pretty bizarre, irrational, and deify logic until they finally die completely.
Don't guess. You're better to go with the steps and calculations Neil outlined.

TRUE GRIT

[krazzz]

After reading some of the last few posts I am beginning to think it may be more of a faulty operator than a faulty engine. I have not be choking it on a hot restart so I was probably flooding it a bit. The only time I tried the choke was after a failed start attempt. I've never had a engine that needed a choke once it was warmed up but I also haven't had an updraft before either. Looks like I have some experimenting to do this weekend.

I will also look into the coil to make sure it is set up correctly. I don't think I am having any coil problems but I also don't want to develop any. Have any of you relocated the coil to a cooler location? I just think it isn't a good design to have something that is heat sensitive mounted directly onto a hot engine block.

[romantic comedy]

Krazz, how were you flooding the engine?

Some guys have moved the coil, while others keep it right on the engine. Mine has been on the engine for 40 years and it is still running fine (with points).

[Dave Neptune]

krazz, it won't flood unless you are choking it. The excess fuel would just run into the throat to be sucked up by the scavange tube once running or drip out of the carb.

Dave Neptune

[JOHN COOKSON]

I just think it isn't a good design to have something that is heat sensitive mounted directly onto a hot engine block.

Where would Universal put the coil but on the engine?
If you are going to sell an engine to a boat manufacturer they will want to buy a complete drop in engine.
I don't like to keep picking on Neil (I know he can take it - as well as dish it out!) but he's worked in the industry and maybe he will add a few words about this idea.
The original design was with points and their shorter dwell time verses an EI and everything worked fine. I, like RC, have had points for 30+ years with no coil over heating issues. Changing from points to an EI can lead to coil overheating problems.

TRUE GRIT

[ndutton]

I don't like to keep picking on Neil (I know he can take it - as well as dish it out!) but he's worked in the industry and maybe he will add a few words about this idea.

Heh, I've been picked on lots worse than this.

Every Atomic 4 I saw in the industry had the coil on the back of the block. That's how they came from Universal and that's how they went into the boats. We're talking hundreds of engines. That doesn't really mean much though. This was in the 1970s before electronic ignition and epoxy filled coils were invented. Coil heat as a problem comes from within, not ambient. Thousands of coils are mounted on the block right next to the exhaust and they work fine for years even with electronic ignition. Mine does as does Roadnsky Jerry's and he's the poster child for ambient heat because he sails, as I've quipped before, on the river Styx (Lake Mead, smack in the heart of the Nevada desert).

Sometimes we're our own worst enemy
We can't leave well enough alone. Along comes electronic ignition and life is good. Well yeah, except that it has twice the dwell of points delivering more energy to the coil and therefore creating more heat internally. In addition we now have epoxy filled coils available (it is an undisputed fact that oil filled coils tolerate heat better than epoxy) as well as adjustable voltage regulators for alternators. Put it all together and the factory original coil saturation balance is thrown out of whack.

I contend our low RPM and only 4 cylinders conspire to keep the coil saturated longer than in other engines and the increased dwell contributes too. We fortunately have, through advisory, failure experience and testing, a benchmark to avoid tipping the coil heat balance: ignition system amperage. The link I provided earlier explains it. As John offered, amperage is a function of voltage (from the alternator) and resistance (primarily from the coil design). Before we dug into this we were screwing up the balance with lower resistance coils, tweaking alternator voltage with the adjustable regulator and going away from the more efficient oil filled coils. We've managed to tame things down by watching the voltage, adjusting the resistance to control the amperage and therefore internal coil heat and managing the heat with oil filled coils.

If this makes EI look like Satan's spawn, not to worry. We have a handle on it now and notice if you will that Moyer's rebuilds all have EI and coils of proper internal resistance and potting material mounted on the block. I can't recall a single reported failure. This is not to say remotely mounting the coil is a bad thing. There's no harm if you're more comfortable doing so.

Krazzz, you said the coil came bundled with the EI. Exactly where did this come from? If it was Moyer, no worries. If elsewhere, then where? I'll go out on a limb and suggest nobody, not even the EI manufacturers, know the intricacies of the Atomic 4 and its ignition requirements better than Moyer and by extension the membership of this forum. This isn't a slam on the manufacturers but rather a defense of them as they really don't know. We are only a microscopic part of their market.