Generator Hunting Under Load

mci7 wrote:
Turbojimmy,
What I was attempting to say was the higher octane provides much longer time before goes bad. On avgas at the 100LL does infact last way over a year in a airplane fuel tank. Why I started using the good stuff in my gasoline engines, like the lawn mower can sit all winter and start & run in the spring like it was just shut down. Can not address why your 454 runs hotter on the better fuel, maybe timing is an issue?
I have converted all in my area using Speeders (rail car) guys to use the better gasoline for the small engines to operate so much better, better idle, start and overall operation. No more gummed up carbs from old gasoline etc.
I have spent 40 years enjoying small engines, how I got into the Onan generator world 40+ yrs ago.
Dave M

Ah - that makes sense.

The higher octane fuel burns hotter, from what I understand. I haven't actually had any overheating issues with the 454. I've only been out on one 300-mile trip with it since I put the new engine in it. After doing a lot of reading I'm super paranoid about engine temp. The maiden voyage was in 85-90 degree weather and it stayed cool for the most part. It did get pretty hot the last 2 miles of my trip coming up a ridiculously steep and long hill at around 45 MPH. I don't have the obstruction of an a/c condenser so I think that helps a lot. Temps were steady the whole trip otherwise.

Anyhow - the generator. I'll have to check the manual for adjustment instructions. The rig sat in a tow yard for at least 6 years before I got it. Obviously I'm running fresh fuel now (I pumped all the old stuff out) but the carb could be gummed up. It fired right up after that long nap, but had a bad plug. I replaced both plugs and it's been running fine ever since. I only recently tried running it with both ACs, though, and that's when the trouble began.

Your issue sure sounds like a matter of governor being out of adjustment, not a weak spring issue, also can be a fouled up carb or combo of both. When you have a proper carb, governor adjusted near correct, it will work very nice & smooth within its ability. The same old story about a 10 ton load on a 5 ton truck still applys.

Turbojimmy,
What I was attempting to say was the higher octane provides much longer time before goes bad. On avgas at the 100LL does infact last way over a year in a airplane fuel tank. Why I started using the good stuff in my gasoline engines, like the lawn mower can sit all winter and start & run in the spring like it was just shut down. Can not address why your 454 runs hotter on the better fuel, maybe timing is an issue?
I have converted all in my area using Speeders (rail car) guys to use the better gasoline for the small engines to operate so much better, better idle, start and overall operation. No more gummed up carbs from old gasoline etc.
I have spent 40 years enjoying small engines, how I got into the Onan generator world 40+ yrs ago.
Dave M

mci7 wrote:
Seafoam is a great help used correctly. And helps when you are too cheap to use a better grade of gasoline. Folks that use a better grade of gasoline do not suffer the same issues. Learned that when did a lot of flying, started using the 93 octane in lawn mower, ATV, rail car (Speeder), generator & chainsaw. No more issues. Do what makes you happy.
Dave M

Thanks. I think....

The 93 vs. 87 octane thing isn't a matter of "cheap". The 93 makes the 454 run hotter so I run 87 in the tank. The 454 is already prone to overheating and vapor locking, so I guess it's a lesser of 2 evils. Just so happens the generator drinks the same fuel.

Been sitting out here for a couple of hours now with both A/Cs on and the idle bumped up a bit. Hopefully I found a happy medium. It's not too high with no load but doesn't seem to be surging under a load.

Bob - thanks for the suggestion. I checked the choke and it's backed all the way off.

Check the choke adjustment.

Seafoam is a great help used correctly. And helps when you are too cheap to use a better grade of gasoline. Folks that use a better grade of gasoline do not suffer the same issues. Learned that when did a lot of flying, started using the 93 octane in lawn mower, ATV, rail car (Speeder), generator & chainsaw. No more issues. Do what makes you happy.
Dave M

Well, it's back to its old tricks. Hunting under a load. It will run one AC just fine. Add the second AC and it starts to surge. I messed with the altitude screw and it didn't seem to affect it. I turned the idle screw in so the throttle would stop bouncing against it as the governor surged. That cured it immediately, but as soon as the load was gone it seemed to be idling way too fast. Unless it was idling too low to begin with?

I assume there's some sort of regulator in these things? That is, if it's idling fast the voltage is still where it should be @ around 120?

Gjac wrote:
You can also pour the Seafoam directly into the crank case before an oil change. The first time I did it I had very hard carbon deposits that I thought was metal until I squeezed then. It really cleaned out the crank case also.

Thanks. I'll try that again next time. I just changed the oil last month.

You can also pour the Seafoam directly into the crank case before an oil change. The first time I did it I had very hard carbon deposits that I thought was metal until I squeezed then. It really cleaned out the crank case also.

My generator was doing the same thing as yours. I treated the main tank with four bottles of SeaFoam and then while I was camping I ran the generator for about five hours straight, Not sure when it stopped surging as I was watching movies but the SeaFoam cured the problem good luck