engine starts but cuts out right away

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olymon

Joined
Jul 6, 2006
Threads
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Location
charlevoix, michigan
Rebuilt my carb on my 77 40 and it ran great after adjusting the idle. Seemed a little cold blooded, but it was cool out. Went out the other day to start it up and it was running like it did before I did a rebuild. I ran it on the road for a while and than it would die if I stopped and idled . It will start and run for about 2 seconds and than cut right out like it looses spark or some kind of circuit opens and kills the motor (sitting in the hot sun while I tried this). The carb was in need of a rebuild, and I did a through job, I even sonic cleaned all the parts at work, and checked to make sure the check balls and power valve were all moving properly.

Is there something that can cause this to happen that is in the emissions circuitry of the 40?? Something in the emissions fuel munbo jumbo? It just doesn't make sense how it ran great and then runs like it did before the rebuild by cutting out. No stumbling or anything, it just cuts out. Frustrating to say the least! I'm waiting for my axles to come in so I can't ride it, but I just wanted to start it up to hear it run:bang:

Too frustrating for a guy with little time to work on my 40. In need of some advice form the gurus out there. A lot of spaghetti tubing running in the engine bay and I'm not sure how many things can make the 40 not run right.
 
crud in your fuel lines?

what does the fuel filter look like?
 
There's a single item that can cause that symptom. It's the idle cut off solenoid.
It's part of the carburetor. It has a wire running to it that should be energized (12v) when the ignition is on. (some models have 2 wires-power and ground). When the ignition is turned off, it should turn off. It's purpose is to cut off fuel flow to the idle circuit when the ignition is off.

Find this solenoid (it's the only electrical connection on the carb).
Turn the ignition to "on".
Pull off this wire and you should feel and hear the solenoid click.
Put it back on and you should feel it click again.
If it doesn't, then check with a tester or voltmeter to see if you have power to it.
 
edwjmcgrath, Thanks for the heads up on how to check the idle cut off circuit.

About a month ago I replaced all of the fuel line with some stainless tubing I had and put in a new fuel filter too. I would guess that the idle cutoff solenoid might be the cause, but why would it work when I first put the carb on and not work the next?? I'll give it a check though, because it cuts out so quickly and efficiently that it just seems to direct, no sputtering or anything like that.

Replace it if bad?, or can I bypass it somehow so it wont be an issue if I drive somewhere and it wants to start acting up again. Does it have it's own fused circuit?

What do you think about putting a separate ground right onto one of the screws on the carb to make sure the solenoid is making a good complete circuit. Seems like bad grounds are half the battle on the 40's
 
Last edited:
Ed probably has the right call, but if it's not the idler solenoid, check your fuses. I recently had an issue where it would start and stay started as long as I had the key turned. Turned out it was just the alternator regulator fuse.
 
From reading through my Gregory's manual, I need to start from square one and check my adjustments on the carb. I think I the the mixture screw is out a little far. What is a normal setting for it? they mention 1 1/2 turns on the carb rebuild paperwork I had. I'm closer to about 4 turns out so I must be out of adjustment somewhere else. I need to go back and forth between idle screw setting and mixture screw setting to get the best rpm at idle and than set the idle to specs.

Like I said before, it was actually running fair set like that, and had good throttle response. Of course, all of this was done while the 40 was up on jack stands waiting for some new axles to show up.
 
olymon said:
edwjmcgrath, Thanks for the heads up on how to check the idle cut off circuit.

About a month ago I replaced all of the fuel line with some stainless tubing I had and put in a new fuel filter too. I would guess that the idle cutoff solenoid might be the cause, but why would it work when I first put the carb on and not work the next?? I'll give it a check though, because it cuts out so quickly and efficiently that it just seems to direct, no sputtering or anything like that.

Replace it if bad?, or can I bypass it somehow so it wont be an issue if I drive somewhere and it wants to start acting up again. Does it have it's own fused circuit?

What do you think about putting a separate ground right onto one of the screws on the carb to make sure the solenoid is making a good complete circuit. Seems like bad grounds are half the battle on the 40's
Click to expand...

Your symptoms don't sound like a fuel filter-that usually shows up under load or high rpm's. If you're not getting enough fuel to idle, the bowl would have to be empty or nearly so. Look through the bowl window and see if the fuel level is in the middle. If so, it's not the filter. If it's empty, start with the filter-it could clog up in 5 minutes from a dirty/rusty tank. Get a clear filter.

The idle solenoid should be on the "engine" fuse. If your tester does not find 12v at the idle solenoid, check out that fuse and/or clean the terminals.

If it works one day and not the next, suddenly, I would guess that it isn't a failed solenoid but rather no power to it. Fuse or bad connection to fuse, wire fell off, something like that. Idle solenoid ground is usually not an issue with a newly rebuilt carb where you just cleaned it up and rebolted it to the manifold.
 
The site glass window shows fuel in it. The tank was "lined" a few years back and with the new fuel lines I tend to think it's the cut off circuit not rust plugging it up. Next is to find some time to tinker with it and see what I have going on. After I check out the cut off I need to get it running and make the proper adjustments to the carb after that.
 
olymon said:
From reading through my Gregory's manual, I need to start from square one and check my adjustments on the carb. I think I the the mixture screw is out a little far. What is a normal setting for it? they mention 1 1/2 turns on the carb rebuild paperwork I had. I'm closer to about 4 turns out so I must be out of adjustment somewhere else. I need to go back and forth between idle screw setting and mixture screw setting to get the best rpm at idle and than set the idle to specs.

Like I said before, it was actually running fair set like that, and had good throttle response. Of course, all of this was done while the 40 was up on jack stands waiting for some new axles to show up.
Click to expand...

FWIW, my mixture screw is closer to 4 turns out.
 
Ed, "FWIW, my mixture screw is closer to 4 turns out."

At least that is a little more comforting. I didn't mess with the idle screws at all during the rebuild, but I did take the mixture screw out when I sonic cleaned the carb parts. I probably have it close enough to do my final tweaking after I get this idle cut off troubleshooting done.
 
@kurtkegger, yep, the ballast resistor could do it too if it was gone.

Olymon, you should also check that you have voltage to the positive terminal on the coil when the key is in the ON position.
 
olymon said:
Rebuilt my carb on my 77 40 and it ran great after adjusting the idle. Seemed a little cold blooded, but it was cool out. Went out the other day to start it up and it was running like it did before I did a rebuild. I ran it on the road for a while and than it would die if I stopped and idled . It will start and run for about 2 seconds and than cut right out like it looses spark or some kind of circuit opens and kills the motor (sitting in the hot sun while I tried this). The carb was in need of a rebuild, and I did a through job, I even sonic cleaned all the parts at work, and checked to make sure the check balls and power valve were all moving properly.
Click to expand...

I had the same issue, after a lot of troubleshooting I narrowed it down to the ignition switch, replaced it and the engine ran fine.
 
Turned the key on and the idle cutoff works fine, clicks every time I pushed the connector back on. Hoped in and the 40 started right up. Ran for quite a while, let it start to warm up and it slowed down in idle and I didn't get to it before it stalled. My 2 year old son was asking "daddy done" about every ten seconds so that put an end to my work for then.

78fj40mg, I have always been a little weary of my ignition switch and had thought about replacing it before. Turning the key to the off position on my 40 will kick in the starter some times so I know something is goofy in there. I was leaning towards getting a new ignition switch before, but this seals the deal. Who would be a good business to get one from.
 
olymon said:
Turned the key on and the idle cutoff works fine, clicks every time I pushed the connector back on. Hoped in and the 40 started right up. Ran for quite a while, let it start to warm up and it slowed down in idle and I didn't get to it before it stalled. My 2 year old son was asking "daddy done" about every ten seconds so that put an end to my work for then.

78fj40mg, I have always been a little weary of my ignition switch and had thought about replacing it before. Turning the key to the off position on my 40 will kick in the starter some times so I know something is goofy in there. I was leaning towards getting a new ignition switch before, but this seals the deal. Who would be a good business to get one from.
Click to expand...

There are many reputable venders:

http://www.cruisercorps.com

http://www.JoeTLC.com

http://www.coolcruisers.com/

http://www.jtoutfitters.com/

plus many more.

Mike
 
olymon said:
78fj40mg, I have always been a little weary of my ignition switch and had thought about replacing it before. Turning the key to the off position on my 40 will kick in the starter some times so I know something is goofy in there. I was leaning towards getting a new ignition switch before, but this seals the deal. Who would be a good business to get one from.
Click to expand...

OH, you failed to mention that. ;)
That's a classic failed ignition switch and could easily cause stalling and intermittent results. I got mine from Cruiser Corps too. I generally prefer oem but at $24 from a reputable vendor vs $60 discounted OEM, I thought I'd take my chances.

Theirs is universal from 69-84. The OEM switch part number was changed midyear in 77 so you would need to know your build date if you go that way.

84450 SWITCH ASSY, IGNITION OR STARTER
84450‑60050 (09/1977 - 06/1980)
84450‑60060 (01/1975 - 08/1977)
 
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