Generator exhaust rusted out

[jillhop]

One of the joys of living in the Northeast--rust! I discovered that the exhaust pipe on my Onan 4000 generator has rusted through. 😞 Do you think that a good muffler shop will be able to fix this, or should I take it to Cummins/Onan? I would think that the entire exhaust system on the generator will need to be replaced. This is on a 1998 Coachmen Class C motorhome. I use my generator a lot, as I dry camp at dog events. Any questions I should ask or issues to be identified before I take it somewhere?

[Gjac]

Glad to hear that it worked out well for you.

[jillhop]

I just wanted to update. The local muffler shop did a great job, had to do a little fabrication to make the transition from the 1 1/2 inch pipe that he had to the 1 1/8 inch muffler pipe. This cost $125. He didn't have a 1 1/8" muffler clamp, but I drove over to the local RV dealer and bought an Onan clamp for $8, returned and he installed that. Nice, neat, professional job.

[jillhop]

Called my mechanic this morning, and he referred me to a local muffler/exhaust place. Took it there, and he said that he could easily fabricate a new exhaust pipe. He has 1 1/2 inch pipe and a pipe bender. 🙂 I'll take it back on Wednesday morning for the fix.

I did also call the nearest Cummins/Onan service center, and they said that it was very difficult to get parts for a unit this old, and they weren't wild about replacing the muffler. I would need to drive it there (1 1/2 hours away) for them to look at to determine if they could even replace the muffler. It looks to me like you would have to drop the whole generator to replace the muffler ... don't want to get into that unless it's absolutely necessary.

Thanks for all the advice--this forum is an excellent resource!

[Chum_lee]

I have the same generator manufactured in 1998 with 1175 hours on it. You can do this yourself, no rocket science, you'll be fine. With two eyes, two hands, and some basic mechanics tools, you will be done in 15 minutes or less. No need to pay $125.00/hour labor for this. Its important that you buy a new muffler WITH a U.S. Forest Service approved spark arrestor like the one you currently have. Unfortunately that means that Onan is your best (not only) choice, BUT, not the cheapest. (no affiliation)

Spray some PB Blaster on the treads about 24 hours in advance and then again just prior to removing the fasteners to minimize the chance breakage.

Chum lee

[Gjac]

I would look at it like this: your exhaust system has lasted 17 years so far, will you keep your MH another 17 years? If not why not replace it with a steel muffler from a low cost muffler shop. If you are willing to do the work yourself, TS sells low cost mufflers and pipes.

[jillhop]

I'm very familiar with the prices at the Onan/Cummins dealer--they replaced the carburetor last summer soon after I purchased the camper. It was expensive, but it runs great/no problems since. I will call them tomorrow morning and see what they say.

Are most automotive muffler shops able to do stainless steel pipes?

[Chris_Bryant]

Keep in mind the muffler should have a spark arrestor. Around here, none of the muffler places carry the right size pipe, so Cummins/Onan is the only choice.

[Vulcan_Rider]

jillhop wrote:
Any questions I should ask or issues to be identified before I take it somewhere?

Use the phone.

I suspect that you are probably overdue for a new muffler too; not every place will have ready access to them, I think.

And the pipes should be stainless if possible. Hangers and brackets should be replaced too.

I think an Onan (Cummings) service dealer is probably your best bet for quality......but not price.

[mpierce]

Greydennyhawk wrote:
When I started mine recently, it had loads of (water) condensation , which was emitted from the pipe, so I think that if it gets crummy, I will have a stainless one made to replace it.

If there is a low spot that collects water, drill about an 1/8" hole in the bottom there, to allow that water to drain out. My Honda Valkyrie motorcycles have them in them.

[Greydennyhawk]

When I started mine recently, it had loads of (water) condensation , which was emitted from the pipe, so I think that if it gets crummy, I will have a stainless one made to replace it.

[westend]

I would think a replacement exhaust pipe might be the best cure. Is the muffler threaded onto the pipe or is it welded?

[ccxnola]

Any COMPETENT muffler shop can make and install a pipe & muffler that will outlast your rig!! Go there, show them the problem, get the options (with prices) and decide what to do!

I recently had the experience of camping next to a large "A" rig (running both air conditioners - so they were inside)with a generator that sounded like a hot, hopped-up Honda reving the engine!!