Welded new muffler on the generator, now it wont' start

[russ240]

Yesterday I had my muffler guy weld in the Cummins Onan Resonator MicroLite MicroQuiet - 155-2449 as mentioned by others previously ... now the generator won't start!

Cranks but does not try to fire at all. If you sniff the exhaust pipe after cranking you can smell propane. The propane switch is turned on. I had the propane tank filled two days ago. Gauge confirms full and stove top works. I used the generator not more than a week ago for several hours and it worked fine. I've probably put 10 hours on it in the last month. Oil level is full. Unit has about 260 hours on it since new. I looked for the open vent tube that gets filled with insect debris as mentioned in another current generator thread ... but mine has a foam sock over then end of the tube and the sock is not particularly dirty. I'm going to pull the sock off and try starting it when I pull it out of the garage next just to verify but that does not seem like the culprit.

I'm guessing that either when he welded it (MIG) he fried something electrically or the vibrations from the sawzall cutting the stock pipe off shook something important loose or broke it.

Due to ceiling height constraints at the muffler shop, he had only the rear wheels on the ramps of his four post lift and had the back end 4 feet up while the front tires were on the ground. I've tried to think of a problem that could have caused with the unit being so far out of level, but I can't come up with one. Unit was sitting back down on the ground before we attempted to start the genny.

I dropped the spare and got a good look through the service access panel but could not see anything obviously disconnected.

The Cummins dealer is booked two and a half weeks out so I set an appt to take it in, but we are taking a trip in the bus this week. I guess I'll bring my gasoline powered Honda gen set with me instead, but I don't look forward to lugging it around and worrying about it disappearing. I have a couple of locks I'll put on it but they just slow thieves down, there's no way to stop them if they come prepared.

If anyone has any ideas on things I might be able to check/fix I'd love to hear them.

[rmkrum]

Check generator oil level?


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[Mcrid]

Looks like good troubleshooting. Since in theory the only thing that changes was the muffler, I'd pass a dowel through the exhaust just to make sure it is clean all the way through (easy). Next I'd check to see if the spark plug is actually sparking (hard).

[russ240]

Originally Posted by russ240

Oil level is full.

Originally Posted by rmkrum

Check generator oil level?


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Yep, checked that.

[Protagonist]

Originally Posted by Mcrider

Next I'd check to see if the spark plug is actually sparking (hard).

Easy for two people. Pull the spark plug but leave it attached to the spark plug wire. With the propane shut off for safety, have a buddy crank the generator while you hold the spark plug (with insulated pliers!) close to the metal of the generator's engine. You should see the spark arc across to ground, especially considering how dark it is under an Interstate.

[russ240]

Originally Posted by Mcrider

Looks like good troubleshooting. Since in theory the only thing that changes was the muffler, I'd pass a dowel through the exhaust just to make sure it is clean all the way through (easy). Next I'd check to see if the spark plug is actually sparking (hard).

Exhaust is clear, I can see right up it with a flashlight (the resonator is a glass packed baffle with perforated pipe so you can see through it).

I'd love to check spark, but I can't even FIND the plug. That access panel does not give you much room to see up in there. Surely you don't have to drop the unit out of the chassis to change the plug (that though reminds me of a buddy of mine in college who had a V8 Pontiac Sunbird) but I can't find it. There are several hoses/lines that COULD be plug wires but I could not pick one I was ready to tug hard on and find out. Ugh.

[73shark]

I'm betting that welding fried something. Too bad he didn't just drop the pipe to cut and weld. Only two studs and the hanger clamp.

[AtomicNo13]

MIG welding can damage electronics. My money is on this theory...

[Amg]

Had something similar when I had an oil change. They also had rear wheels on ramp. That caused the oil to coat I believe the air filter. It cranked and did not turn over. The removed the filter and it started right up. They then changed the filter with coach Off the ramp

[Streamracer]

My unit has a dot plug below the access door you pop out with a screw driver so you can get a spark plug socket to the plug. You still have to reach inside the cover to pull the plug wire which is down toward the bottom.

[J. Morgan]

Propane carburetors can be very sensitive. The flow difference from the added exhaust pipe can throw off the mixture enough that the engine will not want to start.

My guess is that a little adjustment to the mixture screw will make the difference. It will probably want to be set a little bit more rich.


Gradiens super tenui glacie.

[Ralph12]

Did he isolate the ignition system before he welded the muffler on?, might have fried the ignition module

[rmkrum]

Really need to check for a spark, as mentioned earlier.


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[ijustlee]

I guess fried module if electronic ignition. Need to check spark!

[Wolf Alaska]

My Onan 2800 Microlight developed a failure to run condition although it would turn over (crank). I tried several things, but since I doubted the plug was firing took it to certified Onan shop. Testing proved no ignition. Disassembly req'd. There is an ignitor module behind the flywheel/timing wheel that is pulled to get to the ignitor module. Replaced that module & its been running good for 10 years & 400 hours.

You may want to find an Onan shop for this one. I was treated very well & they cut me some breaks on the hours charged because it was such a job. The module was only $80.

Let's Roll. !
Wolf

[J. Morgan]

If the welder placed the ground clamp near the work, the chances of welding the muffler on causing electronic damage is very near nil.


Gradiens super tenui glacie.