351M, genny will not stay running while driving

[Overtaxed]

Your Mr Gasket part is the same one I used.

No matter what else may be wrong, the line pressure is out of spec and needs to be fixed. That may well fix the issue... If not, then you can cross that one off the list of possibles. It is easy and cheap enough to do.

Awesome, I'll give that a shot. Did you put it up front (near the genset)? What did you set it to (what number)? And, I guess maybe I didn't realize, but you did this too (added a fuel pump to your existing setup)? If so, for the same reason or something else?

Sorry for all the questions, if you've followed this thread, AFAIK, I was "alone" in this endeavor/problem. I suspect lots of other people would have this problem if they tried to run their genset underway for long periods of time, but, I do it ALL the time, every time we travel, when we disconnect at home, genny on, and it stays on until we get wherever we're going (our cats ride in the bedroom). And we do a lot of miles over some awful roads, which, for some reason, has always seemed to play into this mystery for us; if the road is smooth, it will generally work fine; as soon as it get rough, we lose the genny, or did until we added the fuel pump.

Anyway, thanks for the help, look like my local Oriley has that part so I'll cruise over there tomorrow and get it hooked in, any details about what/why you did, love to hear about it.

[huntindog]

Awesome, I'll give that a shot. Did you put it up front (near the genset)? What did you set it to (what number)? And, I guess maybe I didn't realize, but you did this too (added a fuel pump to your existing setup)? If so, for the same reason or something else?

Sorry for all the questions, if you've followed this thread, AFAIK, I was "alone" in this endeavor/problem. I suspect lots of other people would have this problem if they tried to run their genset underway for long periods of time, but, I do it ALL the time, every time we travel, when we disconnect at home, genny on, and it stays on until we get wherever we're going (our cats ride in the bedroom). And we do a lot of miles over some awful roads, which, for some reason, has always seemed to play into this mystery for us; if the road is smooth, it will generally work fine; as soon as it get rough, we lose the genny, or did until we added the fuel pump.

Anyway, thanks for the help, look like my local Oriley has that part so I'll cruise over there tomorrow and get it hooked in, any details about what/why you did, love to hear about it.

I set mine at 1 PSI, and installed it just before the genset. It wasn't to correct any issues, as I followed the installation manual to the T. I did not have a remote pump on it, the regulator was just to prevent line pressure rise on hills. I could run it without any issues while under tow.

It was a rather unique install. Onan made an under the floor mount, that I used hanging the genset just forward of the axles. I had a 26 gallon stainless steel gas tank made to supply the fuel.

Pulling that old manual out this AM brought back some memories.. It had a checklist of items that needed doing, and seeing my check marks there was like stepping back in time.

I put over 3000 hours on that unit trouble free, until a lightning strike fried it... We were in the TT when it happened. The entire interior was like a huge orange flashbulb went off.

[Overtaxed]

I set mine at 1 PSI, and installed it just before the genset. It wasn't to correct any issues, as I followed the installation manual to the T. I did not have a remote pump on it, the regulator was just to prevent line pressure rise on hills. I could run it without any issues while under tow.

It was a rather unique install. Onan made an under the floor mount, that I used hanging the genset just forward of the axles. I had a 26 gallon stainless steel gas tank made to supply the fuel.

Pulling that old manual out this AM brought back some memories.. It had a checklist of items that needed doing, and seeing my check marks there was like stepping back in time.

I put over 3000 hours on that unit trouble free, until a lightning strike fried it... We were in the TT when it happened. The entire interior was like a huge orange flashbulb went off.

Great, thanks!

By "1 PSI" you set it to "number 1"? I understand that the numbers on that regulator aren't exact PSI numbers, they are "guidelines". I'll give it a shot, worth trying though!

[offtohavasu]

The soot is interesting. Diesel soot is easy, not enough air, but on a gas you think it would be fouling out the spark plug before soot comes out. I ran mine the weekend from Sea Level to 5k feet. I'll take a look at what the tail pipe looks like when I get home.

[Overtaxed]

The soot is interesting. Diesel soot is easy, not enough air, but on a gas you think it would be fouling out the spark plug before soot comes out. I ran mine the weekend from Sea Level to 5k feet. I'll take a look at what the tail pipe looks like when I get home.

I never would have noticed it if I didn't happen to have the tailpipe right next to the power pole. But it blew chunks, that's for sure. And then looking at the pipe, I could see some soot in there (not sure if that's normal or not, never looked at it before). I'm going to try regulating the pressure down, maybe I'm having the opposite problem now, instead of starving for fuel, it's flooding when I hit bumps and the carb bounces around. Could be letting in too much fuel as the needle lifts up and the pressure is a bit above spec.

So tired of this problem. I've considered just selling the thing and putting an inverter genny in the truck bed. The only thing I really have a genny for is to keep the rig powered while driving and, well, let's say that's been anything but successful.

[offtohavasu]

It can definitely blowing fuel by. I don't know how hard it is to look at the plugs. I haven't dug in to the thing that deep yet. I hope it is a simple as too much fuel now.

[Overtaxed]

OK, got an installed a fuel regulator today, pictures below. I got the one discussed earlier in this thread from Orielly:

https://www.oreillyauto.com/detail/b...r/9710/4514726

Pretty easy install, a few cuts to the fuel line some pipe dope, a few wrenches and done. I set it to the absolute minimum pressure (.5 on the dial), I don't know what that works out to in PSI, but also, I don't care very much, the pump that it's right next to shouldn't require any pressure at all, it just doesn't have much lift, 0 PSI is enough, so long as it's putting fuel into that pump for circulation into the genny. Ran all the ACs at one time to get the genny loaded and see if it starved for fuel, no issues, so I'm going to see how we do at .5 as the setting.

Didn't seem much different, genny always runs great when sitting still. No crap out the tailpipe this time, I did watch for that, but, to be honest, the thing I saw at the campsite was the first time I'd ever seen it blow chunks out the pipe.

We will see, I'm pretty confident I'm getting good fuel into the genny. I did test it while I had the line cut, pushed prime and.. Well, got soaked in fuel. So.. That seems to be as expected.

[huntindog]

OK, got an installed a fuel regulator today, pictures below. I got the one discussed earlier in this thread from Orielly:

https://www.oreillyauto.com/detail/b...r/9710/4514726

Pretty easy install, a few cuts to the fuel line some pipe dope, a few wrenches and done. I set it to the absolute minimum pressure (.5 on the dial), I don't know what that works out to in PSI, but also, I don't care very much, the pump that it's right next to shouldn't require any pressure at all, it just doesn't have much lift, 0 PSI is enough, so long as it's putting fuel into that pump for circulation into the genny. Ran all the ACs at one time to get the genny loaded and see if it starved for fuel, no issues, so I'm going to see how we do at .5 as the setting.

Didn't seem much different, genny always runs great when sitting still. No crap out the tailpipe this time, I did watch for that, but, to be honest, the thing I saw at the campsite was the first time I'd ever seen it blow chunks out the pipe.

We will see, I'm pretty confident I'm getting good fuel into the genny. I did test it while I had the line cut, pushed prime and.. Well, got soaked in fuel. So.. That seems to be as expected.

That should work fine.
I hope this is the fix for you. But no matter what, it was a known issue that needed to be corrected first, And I really think it is the solution.

Really can't fault GD much for not taking care of this when they did the install. I doubt very many people actually run their gensets while under tow.

[Overtaxed]

That should work fine.
I hope this is the fix for you. But no matter what, it was a known issue that needed to be corrected first, And I really think it is the solution.

Really can't fault GD much for not taking care of this when they did the install. I doubt very many people actually run their gensets while under tow.

Well, I most certainly can fault someone. This was one of my first questions to the dealer, "Can I run the genny underway"? They answered "of course". If they had answered otherwise, I wouldn't have bought one and would have just gone straight to the inverter in the truck bed. Then, when having trouble, the dealer (who could not recreate the issue and sent me to Onan) said, "working fine, you should be good to go" (crapped out less than 1 mile from the dealer). Went to Onan, they also told me "should work great" and could not recreate the issue.. Again, crapped out within 10 mins of picking it up.

If it's not supposed to work, well, then, say it's not for use while driving. That's a reasonable position, but I would have saved 4-5K, no need for a genny if I can't use it for the thing I want/need it for. I'd find another way to do it and no harm, no foul. But don't tell me "yes, that will work" if either you don't know or it, in fact, isn't supposed to work that way.

Thing I've wondered now for awhile, while I'm sure you're right, most people don't do this, there have to be SOME people who do, right? Even if you just run it for the 30 mins before you get to the campsite to cool the inside of the rig, I'd just think that this problem would be much more widespread, especially given that there's just almost no way it's going to work in the stock configuration because of the pump lift issue; that should effect anyone trying to do this. I've wondered this for awhile, why am I the only one? Is it just that I do it more? Worse roads in my area? Bigger hills? It just seems like there has to be something at play in my specific configuration that's causing this problem. I'd love it if some other 351M owners with a genny would try to run it for a few hours pulling and see if it craps out for them. Is it me, or is it everyone just not many people running into it?

[FT4NOW]

You're not the only one. I mentioned i use mine underway back in January, look at post #9 . I have 200+ hours on mine, 90% of that is while driving. Like I previously mentioned, the only time it cuts off is when I've gone over some very rough roads. It made it fine from FL to ID so it isnt an altitude thing, I'm very close to 5k feet where I'm at now. The only other times it crapped out is when I noticed the maintenance light came on my OneControl LCD screen, not sure if it was related to cutting off or it was just rough roads.

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