M-37 not starting opinions please

[jzimm]

OK.I need some advice

Trying to get my M-37 running again after about 2 years of setting. I have had it running and it will idle nicely, but if it dies, it will not start again. It seems to flood very easily.
If I wait a day or so, it will sputter and maybe start, but more likely flood out.

The carb was rebuilt a few years ago and I took it off this weekend and did a quick reclean with carb cleaner (nothing major, no plugs removed). I have 24volt electronic ignition and am getting good spark. compression tests OK.......about 90psi avg.......... I think that would be enough for it to at least cough to life a little. Plugs are good and not wet when I take them out.

Currently I have the PCV hole in the intake plugged since that did seem to help it start the few times I have got it running. Besides, when it doesn't start, this is where I can drain the intake of excess gas.

I got it started again this morning and it idled good. Intake vac reads about 15 inches at idle. Up to 20 when I give some gas....no hesitation.
I can adjust the idle screw on the carb almost all the way in and out with no affect. I did finally kill the engine by turning the screw all the way in. Of course after that, it won't start again and when I take the plug out of the PCV port, gas runs out. I wasn't using the choke at all.

My guess is either I don't have enough compression to "suck" the gas in to the cylinders or the carb is pouring too much gas in and needs a rebuild.
Since I have OK compression and it has run and idled well, I am leaning toward something in the carb.

With the carb being in pretty good shape, I ask the experts here if there is a specific item on the carb that would cause what I am describing? Or if I am missing something else I should check.

Thanks for the advice

John

[Gordon Maney]

OK.I need some advice

Trying to get my M-37 running again after about 2 years of setting. I have had it running and it will idle nicely, but if it dies, it will not start again. It seems to flood very easily.
If I wait a day or so, it will sputter and maybe start, but more likely flood out.

The carb was rebuilt a few years ago and I took it off this weekend and did a quick reclean with carb cleaner (nothing major, no plugs removed). I have 24volt electronic ignition and am getting good spark. compression tests OK.......about 90psi avg.......... I think that would be enough for it to at least cough to life a little. Plugs are good and not wet when I take them out.

Currently I have the PCV hole in the intake plugged since that did seem to help it start the few times I have got it running. Besides, when it doesn't start, this is where I can drain the intake of excess gas.

I got it started again this morning and it idled good. Intake vac reads about 15 inches at idle. Up to 20 when I give some gas....no hesitation.
I can adjust the idle screw on the carb almost all the way in and out with no affect. I did finally kill the engine by turning the screw all the way in. Of course after that, it won't start again and when I take the plug out of the PCV port, gas runs out. I wasn't using the choke at all.

My guess is either I don't have enough compression to "suck" the gas in to the cylinders or the carb is pouring too much gas in and needs a rebuild.
Since I have OK compression and it has run and idled well, I am leaning toward something in the carb.

With the carb being in pretty good shape, I ask the experts here if there is a specific item on the carb that would cause what I am describing? Or if I am missing something else I should check.

Thanks for the advice

John

Others use vacuum gauges for diagnosis, so they may say something more definitive, but 15 inches of mercury seems pretty low for idle. If you are tapped into the intake manifold with your gauge, the gauge should read the highest at idle and should drop as you open the throttle. We have some confusing things occurring here.

I am wondering first if/where you have any vacuum leaks. Your suck the gas in scenario is not happening. Not saying it unkindly; just saying it.

I find myself wondering, also, about float level. Thinking out loud, that is not a carburetor we can look in the air horn as it runs, right M37 guys? ...due to the bend in the airhorn at the top. So, we can't watch to see if the balance tube is overflowing.

Float level? Did this ever run right after this, that you term, rebuild of the carburetor?

[Gordon Maney]

jzimm, I got a bounced notification email. Apparently the email address for your account is not working? Please send me a note at the contact us link below. Thank you....

[jzimm]

Thanks Gordon

I updated my email and will be rechecking the float level tonight. The carb was rebuilt by someone other than me about 4 years ago and has functioned fine until now. My quick "rejuvination" of the carb after setting for 2 years just involved a clean out of old fuel and checki of the float valve etc. I suppose I could have disturbed the float setting and will check that out.

I measure vacuum off the intake. I get about 18 inches on my freshly rebuilt WC-63 so I figured it may be a little low, but the engine is by no means new.

Thanks for the advice and I'll let you know if I have any luck.

[Gordon Maney]

Thanks Gordon

I updated my email and will be rechecking the float level tonight. The carb was rebuilt by someone other than me about 4 years ago and has functioned fine until now. My quick "rejuvination" of the carb after setting for 2 years just involved a clean out of old fuel and checki of the float valve etc. I suppose I could have disturbed the float setting and will check that out.

I measure vacuum off the intake. I get about 18 inches on my freshly rebuilt WC-63 so I figured it may be a little low, but the engine is by no means new.

Thanks for the advice and I'll let you know if I have any luck.

In terms of, two years ago it ran fine, and now it does not, that suggests the float level is fine. One possibility is that a piece of dirt was preventing the needle valve from closing completely.

Keep us posted, please.

[Charles Talbert]

90, not good at all

Where did you get the opinion that 90 PSI compression readings are OK? They are not. If these readings are indeed accurate, you need not expect a good running engine at all, in fact at 90 PSI, you will be getting intermitent skipping as a result of low compression and it is also likely the reason you can't restart it when it dies. A decent reading would be 110 PSI or better on all cylinders.

[sixtyninegmc]

90psi will work

90psi is by no means good, but your engine will still run, and will still have enough "suck" to clear the intake of gas. Highest cylinder on my 230 is 80psi and it has been hauling wood for 2 years. Weak, but it still starts and still sucks gas. Not to say it does not need a rebuild, I`m working on it, but I gaurantee that is not your no-start problem. No sense in rebuilding an engine and then having to diagnose existing problems when you should be breaking it in.

[Charles Talbert]

90psi is by no means good, but your engine will still run, and will still have enough "suck" to clear the intake of gas. Highest cylinder on my 230 is 80psi and it has been hauling wood for 2 years. Weak, but it still starts and still sucks gas. Not to say it does not need a rebuild, I`m working on it, but I gaurantee that is not your no-start problem. No sense in rebuilding an engine and then having to diagnose existing problems when you should be breaking it in.

I personally don't believe you can make that guarantee good as every engine with such issues will react somewhat differently making a guarantee from anyone impossible. While yours may run although is weak, another may not. Most probably your low reading issue is simply ring/cylinder wall wear judging by the what you have described, the 1 in question here may be showing up low readings as a result of other issues such as valves. If the intake valves are in part the reason for low readings, the engines ability to suck gas becomes a huge issue. If the engine has not run for some time, it is a very high likelyhood that this may be in play due to stale gas in the system. More diagnosis is needed to confirm anything further.

[Gordon Maney]

The fuel quality issue is a good one. If you are trying to run it on gas that has been in the tank for two years, let's get that out of there and give it some fresh, clean gasoline.

[jzimm]

Thanks for the replys.

It started great this morning and I let it idle for about 15 minutes and then it died and would not restart.

I cleaned out the idle screw passage and I'm pretty sure the float is set right.

In trying to restart it after it died, I noticed no extra fuel at the PCV port after some cranking. Of course there was some there when I used the choke a little later.

so I'm getting fuel and my ignition is switched over to electronic( so no condenosr issues) but she will not even cough at all when trying to start after that 15 min. run.

The coil is only a few years old with very little use on it, but could that be getting hot? I have all the vent lines hooked up.
When it was running, it ran great with no hesitation when applying throttle and good idle.

The fuel is brand new as I drained the tank and ran clean fuel up to the carb the first time I got it out of storage.

[Gordon Maney]

How much fuel is in the tank? I remember doing quite a bit of diagnosis on a truck, only to discover it was literally out of gas.

What happens [a little late now, I realize] if you take of the gas cap after it quit. Does it make the sound of air rushing into the filler neck?

I wonder if the line from the tank to the pump could be restricted. That includes the rubber line to the pump. Do something to see if that line is clear.

[jzimm]

plenty of gas in the tank. As I said, it will run for 15 minutes very well and then die. If I wait several hours, it will start right up again.

I have had the gas cap off the whole time to rule out vacuum lock and I blew out the air cooling line to the distributor also.

Tomorrow, I plan on hooking up a small fuel tank under the hood to gravity feed the carb and see what happens.

[Gordon Maney]

plenty of gas in the tank. As I said, it will run for 15 minutes very well and then die. If I wait several hours, it will start right up again.

I have had the gas cap off the whole time to rule out vacuum lock and I blew out the air cooling line to the distributor also.

Tomorrow, I plan on hooking up a small fuel tank under the hood to gravity feed the carb and see what happens.

Hmmmm.....

I am leaning toward a fuel flow cause as a first guess. Fifteen minutes at idle should not be getting your engine very hot.

We are all sitting here having our popcorn and Pepsi as we follow this....

[jzimm]

Your welcome to drive up north and give me a hand............I can serve you something a little more stout than Pepsi too!!

[Gordon Maney]

Your welcome to drive up north and give me a hand............I can serve you something a little more stout than Pepsi too!!

Thank you for offering. I can't because I am assembling an issue of the magazine just now. Anyway, I am a young person and can't deal with anything more stout than Pepsi.