351M, genny will not stay running while driving

[offtohavasu]

I'm glad to hear it's running properly now. Are you still going to replace the control board if it's running fine with the relays?

[Overtaxed]

I'm glad to hear it's running properly now. Are you still going to replace the control board if it's running fine with the relays?

Yeah, I'm going to replace it. The Flight systems board is much less sophisticated and doesn't shut down on faults. That's exactly what I want, a sensor going out shouldn't take out the generator, IMHO. It's also heavier duty, they said their board can handle the fuel pump load, but since I'm already on a relay, no reason to re-wire it.

[offtohavasu]

Got it. PM sent.

[A.Texas.Yankee]

I ran my generator through large elevation changes through Pennsylvania on half a tank and generator never shut off. I don't think your issue is lack of lift pump.

Sent from my SM-N986U using Tapatalk

[Overtaxed]

I ran my generator through large elevation changes through Pennsylvania on half a tank and generator never shut off. I don't think your issue is lack of lift pump.

Sent from my SM-N986U using Tapatalk

You may be right, however, I'm 100% sure that adding the lift pump made it much, much better. But it might have been a different problem that was the root cause, the lift pump just covered up the other issue.

I will say, however, that was the recommendation immediately from Cummins. And looking at the specs, the pump that's on the generator has a clearly marginal amount of lift for the distances involved. IIRC, I believe the lift was 3' on the stock Cummins pump. The pump has to sit close to 1' above the pickup in the tank, getting another few feet by going uphill or being slightly nose high, not at all difficult to do.

I do suspect that for most people it works, but it's easy to see how you could wind up with a problem in some situations with the stock configuration.

[offtohavasu]

You may be right, however, I'm 100% sure that adding the lift pump made it much, much better. But it might have been a different problem that was the root cause, the lift pump just covered up the other issue.

I will say, however, that was the recommendation immediately from Cummins. And looking at the specs, the pump that's on the generator has a clearly marginal amount of lift for the distances involved. IIRC, I believe the lift was 3' on the stock Cummins pump. The pump has to sit close to 1' above the pickup in the tank, getting another few feet by going uphill or being slightly nose high, not at all difficult to do.

I do suspect that for most people it works, but it's easy to see how you could wind up with a problem in some situations with the stock configuration.

Add other variables, such as heat, and the demand on the stock pump goes up even more.

[Overtaxed]

Flight systems board installed today. They were great to deal with, and helped me find the right board. And the right board it was, fit right in, generator fired right up. No shutdowns since it's been installed but the real test comes tomorrow, going to wait for a solid 90-95 degrees, fire it up and see if it holds it together. Fingers crossed. Honestly, this SHOULD fix it, there is basically nothing left that it could be; I suppose I could do the carb too, but the generator runs like a kitten when it's not blast furnace hot out, I don't see how the carb could be the culprit.

One interesting thing on the flight systems board, you know how when you use the rocker switch to prime, then press "start" and there's a delay? No delay on this sucker. You press start, it's like connecting the 12V positive straight to the starter. It's very noticable, anyone who's messed with this generator would pick up on it immediately and know it's got a non-stock board in it (could be useful if you're buying used, I suppose).

Other than that, seems identical. Reporting correctly to OneControl, remote start works fine, both fuel pumps running. It was a super easy swap, after all I've been through, I was figuring this was at least a 3 beer and much cursing job. Nope, I was in/out in <1hr. Only takes on size socket wrench and a few extensions to do the entire thing (the extensions are needed to get at the bolt in the back and make the front bolts a whole lot easier). Again <1hr start to finish, and that's me never having done it before. Could probably do it in <30 mins now.

Cross your fingers for me, please!

[Overtaxed]

Well, it's not the control board. <sigh>

Fired up the generator getting ready to leave on my trip in the driveway, outside temps around 90-95 degrees. Ran great for about 1-2 hours, then.. I heard it.. Surge, surge, sputter, die. Same symptom I have been chasing for close to 2 years now.

I was running 2 ACs, so there was a pretty significant load on it, but, of course, it should be able to handle 2 ACs (and not much else).

I've got a few things left to try, but it's getting down to something either in the motor or the generator itself that's failing when it gets hot. My best guess right now is magneto or something in the electrical (spark) system that's getting hot and then losing spark when it overheats. I checked the carb bowl, full of gas, then did a restart, just like before, the restart was tough, it really didn't want to start again (whatever is hot, if you try to restart quickly, it's still hot and not working well is my operating thesis).

I'm thinking of doing the plugs because it's relatively easy and will rule something out, but I've never heard of plugs failing when they get hot.

Ideas/suggestion?

[powerscol]

Well, it's not the control board. <sigh>

Fired up the generator getting ready to leave on my trip in the driveway, outside temps around 90-95 degrees. Ran great for about 1-2 hours, then.. I heard it.. Surge, surge, sputter, die. Same symptom I have been chasing for close to 2 years now.

I was running 2 ACs, so there was a pretty significant load on it, but, of course, it should be able to handle 2 ACs (and not much else).

I've got a few things left to try, but it's getting down to something either in the motor or the generator itself that's failing when it gets hot. My best guess right now is magneto or something in the electrical (spark) system that's getting hot and then losing spark when it overheats. I checked the carb bowl, full of gas, then did a restart, just like before, the restart was tough, it really didn't want to start again (whatever is hot, if you try to restart quickly, it's still hot and not working well is my operating thesis).

I'm thinking of doing the plugs because it's relatively easy and will rule something out, but I've never heard of plugs failing when they get hot.

Ideas/suggestion?

You say magneto - does it have a standard distributor with points or is it and electronic ignition? I know old distributors with points are rock solid except for moisture if put together, lubed and gaped correctly, I also know ignition modules modals can fail when hot. Where are those components located and can you move or insulate them?

Just brainstorming here

[Redapple63]

These generators have a coil to generate the spark.