carb cleaning

[George]

Dennis,
For over 45 years I've had good luck cleaning carbs with Lacquer
thinner there ain't much to those little carbs and if you are carefull you probably will save the gaskets. I don't put the gaskets in thinner as it swells them and does funny things to em (kinda puckers them ) from your threads, you most likely have crud/& gummy deposits in the bowel & jets,clean everything and blow good with compressed air. don't use anything that would damage or enlarge the passages or jets like a drill bit just use common sence and it should be a success, rememder, it worked before it sat for a while so it will again. gas tends to turn to a varnish like goo and smells awfull. that's a shure sign of needing a good cleaning also it might be wise to look for a good flow TO the carb.
ol'Geo.

[87MH]

Thanks, George.....

Your recommendation sounds like a plan.

I have gaskets, plugs, lots of really nasty chemical cleaners, copius quantities of cold adult beverage, and no desire to go to a crowded campground this weekend.....just me, the pups, and the Onan.


I anticipate that at least one of us will be put straight prior to punching in on Tuesday.

Thanks again for the hints.

[PeterH-350LE]

Originally posted by 87airstream345
...just me, the pups, and the Onan.

I played that game before. It's fun! And I always succeeded in getting them to run great in the driveway. As soon as I hit the road they would promptly forget our previous agreement. I swear they are alive and revengeful. I am not just talking about 1 onan, no, I had relationships with several of them. They are all alike. Tough as nails, noisy and dependable until the carb goes. Then you take it apart, clean it up and put it all back together and mess with the adjusting screws. And lo and behold it runs...until you hit the road. Then it dies.
Then you finally figure out that the governor shaft is wobbled out at he carburetor and it is sucking air.
A call to Onan reveals the fact that the carbs are NLA. But they usually only tell you that after you already spent several hundred dollars for all the cool tune up stuff and in some cases $200.- plus for a new circuit board.
So now what, is what I ask the Onan dude? He said: boat anchor!
Some folks have found carbs on ebay for ~100.-.
I just bought a Honda when my last Onan wanted to play.
Another amusing thought is the hours people claim. 1985 325, original onan 6.5 with 87 hours. If you do the proper maintenance and run it just 1 hour every 2 weeks, which is 26 hours/year times 18 years= 468 hours=time to decarbonate the heads
just some rambling, good luck!
Don't kick the dogs...

[87MH]

A quick update on the Carb rebuild.

Carb is off, disassembled, gone through, and repainted, waiting for a break in Tropical Storm Grace for installation.

No major problems. The Throttle Linkage Spring Tension adjustment rod failed in tension during disassembly. Good time to fail. Have Southern Engineered a much stronger tension control, had to drill the previous 3/16" mounting plate hole to 5/16" to accept a 1/4 " thread.

I did find a repair necessary to the Top Air Deflector Plate (16" X 22"). The support for the Center Mounting Bolt was cracked about 80%. A short bead with the MIG will fix it. Apparently the two side mounting points were reinforced at the factory, and no cracks were evident.

Also tore into the fuel pump to check the filter. Everything was fine, except THERE WAS NO FILTER!!!!!. I would suspect this is another fine example of ".....if you want it done right, do it yourself". At any rate, the carb bowl was relatively clean, the only major piece of debris caught just below the fuel level valve.

Due to the absence of an internal filter in the fuel pump, an external filter mounted upstream of the fuel pump will be in place prior to cranking the genset.

Plugs and points were replaced. I could not find paperwork from the PO indicating when this had been done last. Genset hour meter now indicates 733 hours, but plugs and points indicated that this maintenance should have been done quite some time ago.

Total time invested so far is 5 hours, cost is about $200 in parts. I am not at all concerned about the time it is taking, since more than half of it is cleaning and repainting. Another example of the benefits of not having to "hire it out". as opposed to "doing it yourself", and knowing it is done correctly, and doing it when the opportunity presents itself.

It did require excessive torque to break the plug seat. It never ceases to amaze me how tight even "knowledgeable" people crank these threads down. No evidence of "never sieze" or any other lubricant on any bolts removed so far.

Many thanks to George and Peter for their hints so far.

[ALANSD]

I guess I am lucky- Onan has 480 hours on it, runs well except for the occasional stalling recently when rounding a sharper corner.
Cleaned carb in the spring, new air filter, cleaned spark plug and regapped..ran some Marvel Mystery oil thru it and all is well.
Ran for days on a recent trip keeping the a/c and frig goiing while on the hiway.

[87MH]

Right now, I would have to call this weekend an even draw.

The Onan is running pretty smoth at an idle, but just when I was going to adjust the primary jet I was cold cocked by Murphy's law!

With the engine running smooth at idle, I went inside to turn on an AC to load the genset. Onan running rough. OK, hurried outside to adjust primary.

Discovery No. 1
If one does not fully turn the oil dipstick/filler cap fully to the detents, said filler cap Can and Will jump right out of the specified fill/check hole, and the ONAN will through nasty, smelly oil ALL OVER the place.

What a mess!!! It got all of my tools, two toolboxes, the genset, and the entire parking area.

Drug out the pressure washer, fired up the Honda, moved all the other vehicles and the MH and enjoyed a full afternoon of pressure washing used oil off of the drive and the road side of the 345.

At this point, I decided it was a pretty good time to change the oil in the Onan.

Discovery No. 2.

If anyone knows the joy of changing a filter on a lycoming aircraft engine, they know that it is impossible to avoid about a pint of oil being lost when the filter is unseated.
Ditto with the ONAN. The only difference is, with the ONAN you can't get to the bottom pan with a rag to clean up the mess.

More wand time with the pressure washer.

So, with a rebuilt carb, a fresh oil change, and clean tools and work area, I'm ready to set some voltage levels, right?

Discovery No. 3

LCD Voltage/Ohm/Amp meters are NOT impervious to hot motor oil, and definitely will give erroneous readings when attempting to use them after an oil shower.

Bummer.

The bright side of the weekend?

I get to go to Sears tomorrow and purchase another meter, and have the rest of the week to look forward to outsmart that pesky Onan.......

That is, if I can stand enough shower time to rid myself of the nasty "used oil" smell that has permeated my hands.......

Heavy sigh and open another cold one.

[74Argosy24MH]

Ditto with the ONAN. The only difference is, with the ONAN you can't get to the bottom pan with a rag to clean up the mess.

I drilled a half inch hole in the bottom of mine for the same reason. Pretty good design isn't it?

John

[PeterH-350LE]

Hmmm, Dennis, started to worry about ya..
Are the pups ok?