Generac Impact NP36 runs a long time then chokes out

DeDONRAGE · May 29, 2020, 12:39 AM

Ok I have this Generac Impact NP 36 Variable Speed Mobile Generator in my 89 Winnebago Warrior that is sticking it to me. I get it running and think its good to go then when I use it it starts messing up again.

First this is what its doing. It will run like normal. I let it warm up then switch the AC on. AC blows cold and all is good. It will do this for hours. Then it will start to choke or cut out. It like idles down then revs up and keeps repeating this until I shut it down.

What I have done to it so far is all the obvious stuff. I changed the oil. Changed the oil filter. Changed the fuel filter. Changed the spark plug. Changed the air filter. After all this its still not fixing the problem. Well I test it and it runs for several hours. I think ok its good then I take it out to use it and several hours in it messes up. This time I was running it for about 3 hours a day. Third day it messed up again.

Does anyone have any ideas of what this might be? Maybe what I should try to look at next?

Thanks

ClydesdaleKevin · May 29, 2020, 08:32 AM

Might be the control board. Or even points if it has them.

Kev

Rickf1985 · May 29, 2020, 09:10 AM

I have never heard of that setup but running for a long time and then acting like running out of gas could be a coil going bad since you have already checked the fuel related items.

Rickf1985 · May 29, 2020, 09:15 AM

I just Googled that set and I came up with a much newer computer controlled set. I suggest you get the manual and go through it. The one I see is 3600 watts which is a bit small to be running AC and an RV.

http://eldonrv.com/public%20announcements/Generac%20Impact%2036LP%2015971.pdf

Froggy1936 · May 29, 2020, 03:34 PM

I have experienced a similar problem due to overheating from lack of air circulation A small electric fan mounted in the compartment blowing on the engine cured it Frank

DeDONRAGE · June 01, 2020, 02:20 PM

Let me ask this do I need to open the door to the generator when running it? I mean I leave it closed.

Froggy1936 · June 01, 2020, 03:46 PM

On mine i have a 12 in radiator fan mounted on the door, on a separate switch! Also a 110 V fan mounted behind the New unit. I had the overheat shut down with the older Honda unit also, as the compartment is very well sealed an insulated to cut down on the noise ! And mouse and squirrel intrusion ! See my pictures in photo section and installation on projects section Frank

Rickf1985 · June 01, 2020, 05:29 PM

Frank has a general purpose generator so he needs to get extra air in and out of the compartment. A standard RV genset is designed to pull outside air in through the louvers in the door and exhaust it out the bottom after pulling it through the genset to cool the generator. The picture of the one I see when I pull up the number you give shows an RV type genset with that type of cooling. Does yours pull cool air in the door and blow it out the bottom? If it does then any fan you put on there will probably be more of an obstruction than a help since it should be pulling a lot of air on it's own. Mine has no louvers in the door but the Onan is set up to pull the cool air from underneath at one end and blow the hot air back out the other end, again underneath.

DeDONRAGE · June 04, 2020, 04:45 AM

Well on a side note I tried to start it yesterday and it was a no go. Acts like its not getting fuel. Maybe the carb is just gummed up? The only thing I can think of. I think Im going to take it to small engine repair shop up the road this week. Or I might just try to mess with the carb myself. I rely on this 3 to 4 days a week. Its getting too hot to run without air.

Rickf1985 · June 04, 2020, 08:33 AM

Is this the same unit I linked to? If so it is a computer controlled unit and it could be a lot of things. If the carb is getting fuel then it is probably not the carb. Could be a bad control unit or something as simple as a dirty ground on the control unit. You are going to have to go to a place that services those particular units.

DeDONRAGE · June 04, 2020, 04:06 PM

Is it worth having it worked on or should I look to upgrade it? Im not a fan of the inverter setup since I have to lug around extra fuel. Id prefer to use the onboard fuel tank.

Rickf1985 · June 04, 2020, 05:09 PM

I can't speak for that, I don't know anything about this particular generator but I can tell you that inverter generators are much more efficient than old school run full bore all the time ones. And unless you find an older Onan then you are looking at something like Frank did and those run at 3600 RPM as opposed to the Onan's running at 1800 RPM. Needless to say which is going to use more gas. Or you can go with one of the quiet inverters like the Honda 3000 or it's Chinese clone from Harbor Freight. You can stand right next to those and barely hear them running.

DeDONRAGE · June 04, 2020, 05:31 PM

Im using the one from Harbor Freight now. I like it. Just sucks having to keep filling it up. But you think that's a better option than having this one worked on? Convert compartment for additional space?

Rickf1985 · June 04, 2020, 08:30 PM

I think the one you have there is the best option as long as you find someone that knows how to work on it. That may not be all that hard to do, you have to remember, I am an old guy who works on engines and automotive electrical systems. RV generators are sort of on that, "I can fix it with the right manual" list for me. But what you have is an RV specific generator, that is a lot better than adapting a general purpose generator to work in an RV. There are a lot of safety issues to deal with like exhaust and wiring in adapting a general purpose generator.

DeDONRAGE · July 10, 2020, 05:58 PM

So I guess I figured out a little bit by accident. Just thought I'd drop an update here. I thought when I first bought this that the generator would run down to 1/4 of a tank. I don't remember if I ever tried it. But its plumbed into the main gas tank of the RV. I definitely understood it would run down to a 1/4 anyway. But regardless I have been going to 2.5 weeks it runs fine as long as I keep it above half a tank. So somehow the level of fuel below a 1/2 a tank of fuel is preventing it from getting fuel. That's what it was doing it was starving for fuel so it would just die. But its working now. I just have to keep it fueled up. LOL

Oz · July 11, 2020, 04:52 PM

I do recall reading in other threads that the generator fuel lines were intentionally set at a higher level in the fuel tank to prevent the generator from using up all the fuel needed to run the engine. That could easily happen.

DeDONRAGE · July 14, 2020, 03:32 PM

Yea just thought it was at a 1/4 But I guess its at 1/2. But good to know.

Rickf1985 · July 14, 2020, 08:44 PM

Doesn't sound right. Mine is at less than a quarter right now and it is still chugging along. I know it will die out soon but 1/2 is too high. Something going on with the pick up.

Elandan2 · July 19, 2020, 08:14 AM

Are you relying on the fuel gauge reading 1/2 ? Maybe it's just the gauge is inaccurate. i??