Generator preheat problem

[dog walker]

Recently returned home in tail end of early major cold snap.Was able to keep water pipes from freezing despite temps in low 20's two nights in a row. It was a real challenge to get the Onan7.5 kw to start. I have a preheat plug on the coach Cummins engine and used it. Looking for a way to preheat the Onan diesel. Can't find anything in the manuals. Any suggestions? Can you use a "dip stick" heater?

Thanks for your help.

[jerichorick]

I think your Onan preheats when you hold the start/stop switch in the stop position. This is also the primer method. But your fuel may have been the problem. A heater under the fuel tank in those temps is not a bad idea along with some skirting.

[HarveyP]

Some of the diesel treatment for cold weather is also necessary. It may also be called anti-gel. Available at any auto parts store or even at Walmart. good luck, Harvey P

[Mr_D]

At +20 you shouldn't need any anti gel if you use winter blend diesel, if you didn't get the winter blend than yes, I'd add the anti gel. But even then you'll need to run the engine for a while to mix it in.
I need to get our tank filled and will add the anti gel at the station before fueling up and then drive home. That will mix it up enough.

[pumper9x9]

You can call the closest Cummins Dealer and ask if they have a block heater that will work on your generator.

[dons2346]

The Onan generator uses a glow plug for pre heat. You can activate it by holding the start/stop switch in the off position as stated above.

I have started mine at 4 degrees with no problem.

[Tony Lee]

You can activate it by holding the start/stop switch in the off position as stated above.

I thought the (longish) time delay between switching to the start position and when it actually started cranking was to allow the glow plugs to do their preheat.

Further thought that holding the switch in the off position was just a fuel-prime operation.

[okgc]

Further thought that holding the switch in the off position was just a fuel-prime operation.

X2...

[jerichorick]

This may help all: http://www.cumminsonan.com/www/pdf/manuals/981-0161.pdf

[OLYLEN]

There are fuses in the radiator fill area. You take the bolt loose take the cover off pull the radiator fill hose out a bit(then get the wife with small hands to) pull the fused links out. This was a problem on mine until the glow plugs went south and needed to be replaced. After replacement temp is not a problem. Mine before would give me a hard start at 40 degrees and by 20 forget it.. As I knew the plugs were dead I would have the wife turn the gen over and use start fluid until I could get home for repairs. But be careful if you do have wife turn gen over, keep on the turning over as you do just the smallest of fluid.

LEN

[dog walker]

Thanks for some great input. Follow-up question: are the glow plugs sufficient to allow the diesel to start in 20+ degree weather? The way the genset is shrouded it looks a bit challenging to get a typical radiator hose coolant heater to fit. When home, I'll check the glow plug fuse. Not sure how to check the glow plugs themselves.

[dons2346]

Originally Posted by dog walker

Thanks for some great input. Follow-up question: are the glow plugs sufficient to allow the diesel to start in 20+ degree weather? The way the genset is shrouded it looks a bit challenging to get a typical radiator hose coolant heater to fit. When home, I'll check the glow plug fuse. Not sure how to check the glow plugs themselves.

See post #6

[jerichorick]

Originally Posted by dog walker

Thanks for some great input. Follow-up question: are the glow plugs sufficient to allow the diesel to start in 20+ degree weather? The way the genset is shrouded it looks a bit challenging to get a typical radiator hose coolant heater to fit. When home, I'll check the glow plug fuse. Not sure how to check the glow plugs themselves.

-20* according to the manual I posted. The generator needs a bit of time to come up to speed and power when you start it in cold weather, more so that at 65*. The ATS may only be timed for "proper conditions" before its timer starts and this may be too short under those conditions. Shutting off the generator breaker during warmup will prevent early loading. You can hear the generator stabilize as it warms up. Close the breaker (front panel of the generator) and then the ATS will do it's job, loading the generator properly.

[Tony Lee]

Originally Posted by dons2346

See post #6

See post #7 and #8

And post 9 for the manual.