Onan microlite 2500 lp intermittant start

[socalfun]

Hi All,

I have onan microlite 2500 lp generator in my Forest River MB Cruiser on 2004 Sprinter Chassis.

It was working fine for all these years and recently it won't start regularly. I changed out air filter and spark plug but to no avail. It starts sometimes. Gas is full and battery is good. Any input will be greatly appreciated!

[Gene_in_NE]

socalfun wrote:
Well I left main gas valve open then it starts EVERY TIME!!! When I close the valve for about 30 min, open valve and try to start immediately, it won't start. I wait for another 30min while the valve is open then it starts right up. I think gas delivery might not be at its best. Anyone has any explanation for this behavior?

From your description, I am only guessing that the valve you close is the propane supply. If the generator is not running, it is possible that the line from the shut-off looses the propane to someplace. Then if you try to restart, the line from the valve to the carb (or injector) is full of air and needs to wait until the line is filled with propane.

As you describe your routine above, what happens if you open the valve and wait for those 30 minutes - does the generator then start right up? Sounds like the line fills with air and it takes a while for the air to be purged out.

My gasoline lawn mower acts the same way. If I close the valve under the gas tank, the next time I try to start the mower; I have to wait until the gasoline fills the carburetor. The gas evaporates from the carb between mowings.

[socalfun]

Well I left main gas valve open then it starts EVERY TIME!!! When I close the valve for about 30 min, open valve and try to start immediately, it won't start. I wait for another 30min while the valve is open then it starts right up. I think gas delivery might not be at its best. Anyone has any explanation for this behavior?

[loving_retireme]

socalfun wrote:
Hi All,

I have onan microlite 2500 lp generator in my Forest River MB Cruiser on 2004 Sprinter Chassis.

It was working fine for all these years and recently it won't start regularly. I changed out air filter and spark plug but to no avail. It starts sometimes. Gas is full and battery is good. Any input will be greatly appreciated!

Need more information, "it won't start regularly." Does that mean that sometimes it starts and other times it appears to start, but the moment you release the start button the engine ceases to run. If so, this is one of the symptoms of a failing electronic voltage regulator and typical repairs run from $500 to $700. Mine took a few months to completely fail.

[gdoug83]

Might be a clogged vent tube. Located on passenger side of generator at the bottom. Sleeve type black foam filter. Yes, regulator could go bad. When my generator gave me start problems it was the oil level.

[socalfun]

Oil level is good. I read somewhere if the vent tube is clogged it won't start. Is it right? Not sure where it is located. Also is it common the regulator goes bad over time?

[gdoug83]

Check the oil level? A common reason for no start is low oil level.

[gonetothedogs1]

I had problems with my 2007 LP gas generator on my RT SS Agile last summer. The regulator was replaced and I was told an oily substance was found. Mechanic surmised it was from the odorant used in the gas which, over time, accumulated in enough concentration to clog the generator.

[401nailhead]

Sorry, my mistake. That shows what little I know about the microlites, since the one that had been in our B was gone by the time we purchased the vehicle. I'm just used to the portable home generators, which can have similar problems to yours but run on gasoline. I see now that you said lp. I'll be quiet now and sit back and learn! Good luck!

[socalfun]

Actually it is propane model.

[401nailhead]

My most common problem with small gas engines in the last 5 or 10 years has been old fuel, water, or deposits in the small carbs. It is gasoline, correct? While I remember warnings on gas freshness going back decades, I have only had the significant problems in the last decade. You may want to spray some carb cleaner through, and that also acts a as quick start substitute. I have been know to use quick start (especially on old cars with carbs and choke problems), but I was warned that using too much can damage the engine (makes sense). The practice of running the fuel out, using fuel stabilizers, and keeping clean carbs is becoming more and more important. My own current task is to get the home back up generator working again after letting fuel sit too long.