Problems with 20kw gen-set

[Toyboy]

I have a 2 year old Generac 20kw installed and running on NG that has not started for scheduled weekly exercise 2 out of the last 4 weeks. It cranks over but will not fire up. It turns, just won't catch. Try's for 5 times before it cancels out the exercise. Now before you start running Generac down let me fill in the blanks.

For the last two years it has faithfully run it's scheduled 15 min exercise without a hitch. Now I live in Northern WI, and ever since before Thanksgiving it's been colder then a well diggers arse, with temps running between +15 to -30. Most days it never gets above -6. Nasty cold spell which you already know about.

Now when it was installed, the gas company replaced the meter on the house with a larger one to accommodate the increased demand. The unit has a regulator that was originally set at 7" of water. Generac calls for 5 to 7" of water column (0.18 to 0.25 psi). Apparently the unit has a auto shut down if gas pressure gets too high. Gas people came out today and checked for pressure and volume and all is within spec. They did back down the pressure to the gen-set to 6" to see if that would make a difference. They thought it may be too close to the high side. I won't know for sure unless I go fire it up at -25 tomorrow or till next Sunday if it did.

Do any of you gen-set gurus have any ideas on what may be the issue, or do you think by lowering the NG pressure may do the trick?

Ideas?? Thoughts?

 

[zzvyb6]

Valve closed, no ignition, air in line, cosmic rays, global warming, Affordable Generator Act.

 

[RJFEJF]

Load test your batt, and check your trickle charger.

 

[Toyboy]

Battery is good and so is trickle charger. It cranks over ok, it just acted like it's being starved for fuel. The first time this happened ( 2 wk ago) it would rev up & die. Done that a couple times before it caught and stayed running.

This time it popped a couple times and backfired through muffler. Went outside and hit manual start and I'll bet it didn't turn two revolutions and away it went. Perplexing!

 

[RJFEJF]

Did you try changing the spark plugs? I had one bad spark plug out of the 2 plugs and it acted the same.

 

[Toyboy]

No I didn't. The unit only has around 30 run hr on it (12 hr yr). It's only run the exercise cycle because we've not had an outage since it's been installed. I did service oil & filter this fall (Mobil1 5w30), but the air filter looked new so I left that alone.

 

[Industrial Toys]

A friend of mine in the commercial generator business would say, the problem is that it is a Generac!
Has nothing good to say about them.

How many RPM does the unit run at, just out of curiosity?

I actually installed one (on Propane) at the request of a customer. My feeling, and hearing the thing run at 3600rpm is that it won't last long! Maybe the regular excercise has already worn it out.

 

[RJFEJF]

I would put in new plugs every year. I had skipped 1yr and wouldn't ya know it was 1 bad plug and both plugs did look good before the change out. You need fuel, air and spark, this is usually were problems occur, barring any mechanical break down.

 

[tcartwri]

Nat gas and propane motors hate the cold. end of story.

 

[Toyboy]

A friend of mine in the commercial generator business would say, the problem is that it is a Generac!
Has nothing good to say about them.

How many RPM does the unit run at, just out of curiosity?

It's a V Twin rated 36hp at 3600 rpm.

I'm not into bashing any brand, I just want to sort out what the problem is with mine.

If I needed a commercial gen-set it would be a Cat.