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Onan Generators

Onan 7.5 JB 3CR/2442T Added to the Fleet


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  #31  
Old 03-20-2018, 10:44:10 AM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

Wayne what do you mean by saying running the mechanical pump dry is not a good thing?

That statement applies to submersible fuel pumps like those found in autos, not the Onan JBs. I have been running mu JB gasoline fuel,pump "dry" now going on 48 years without a problem. BTW! I never used gasoline in my JB even though it was designed for it.

EICBob are you aware of the fact that if your JB was equipped with a "gasoline-only" carburetor and you convert to propane, this can be done and your JB will run on propane but the internal parts, like the valves, valve guides, the oil cooling line restriction, to name a few may wear out sooner that expected. Reason being, the JBs designed for gasoline-only took advantage of the fact that the leaded gasoline operated at a lower temperature and the lead had a beneficial lubricating affect on the components subjected to high temperatures. So Onan used for lack of a better term, lower quality, softer metal parts in those plants. Don't believe me? Then look at the different part numbers for such items like, valves, valve seats, valve guides, etc. Refer to 967-320. Propane burns hotter than gasoline and there is not vapor inhaled, just a gaseous mixture.
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  #32  
Old 03-20-2018, 10:47:21 AM
consolenut consolenut is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

Hi bob thanks for the reply. I was hoping It had a gasoline carb and you needed a gaseous carb.
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  #33  
Old 03-20-2018, 11:35:01 AM
Wayne 440 Wayne 440 is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

Quote:
Originally Posted by Leon N. View Post
Wayne what do you mean by saying running the mechanical pump dry is not a good thing?...I have been running mu JB gasoline fuel,pump "dry" now going on 48 years without a problem. BTW! I never used gasoline in my JB even though it was designed for it...
I mean just what I wrote- that running a mechanical fuel pump dry is not good for it. The mechanical pump, running dry with no back pressure, strokes much further than its usual travel under normal conditions. That creates undue stress, and often premature failure of the diaphragm.

You may run your pump "dry" with no readily apparent issue. The fun starts when you put fuel into it and end up with a leak, crankcase full of gasoline or both.
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  #34  
Old 03-20-2018, 02:08:43 PM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

OK Wayne I will grant you that, and I have no evidence of oil leaking from the fuel pump. However, hopefully I will never have to run my JB on gasoline.
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  #35  
Old 03-20-2018, 02:13:10 PM
EICBob EICBob is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

Quote:
Originally Posted by Leon N. View Post
EICBob are you aware of the fact that if your JB was equipped with a "gasoline-only" carburetor and you convert to propane, this can be done and your JB will run on propane but the internal parts, like the valves, valve guides, the oil cooling line restriction, to name a few may wear out sooner that expected. Reason being, the JBs designed for gasoline-only took advantage of the fact that the leaded gasoline operated at a lower temperature and the lead had a beneficial lubricating affect on the components subjected to high temperatures. So Onan used for lack of a better term, lower quality, softer metal parts in those plants. Don't believe me? Then look at the different part numbers for such items like, valves, valve seats, valve guides, etc. Refer to 967-320. Propane burns hotter than gasoline and there is not vapor inhaled, just a gaseous mixture.
Hi Leon...
I am hoping that because the plant came built from the factory with a tri-fuel carb installed, option C1 on the build sheet, Onan took that into consideration and the internal parts you mentioned are up to the task. Thank you for the warning about the differing internal parts.

-Bob
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  #36  
Old 03-20-2018, 04:10:36 PM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

Bob you are all set. No need to worry. The tri-fueled J-Line plants had the harder steel (satellite) valves and several other related parts as opposed to the gasoline- only designs. I found that out when I refurbished my JB since I had to replace some valves and valve guides because of excessive wear do to lack of lubrication and high temperatures.

In my situation, the JB was operated exclusively on propane and the oil line to the valve chamber was plugged. Onan even calls out a different oil line flow restrictor depending on the type of fuel.
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  #37  
Old 03-24-2018, 10:15:58 PM
51f1 51f1 is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

I'm thinking about putting my 7.5 LPG fueled model on a Harbor Freight wagon. HF says it will hold 1,000 pounds, which I doubt. Anyone have a guess as to the weight of this generator? Thanks in advance.
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  #38  
Old 03-24-2018, 11:11:12 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

LeonN. says his magniciter equiped JB is 475#.
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  #39  
Old 03-25-2018, 06:49:03 AM
EICBob EICBob is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

With a battery and the output box, my 2 JB’s (one is a YD and the newbie is a magniciter) both weigh in at approx 525 lbs each.
I made my carts out of 2x6 lumber with industrial wheels.
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  #40  
Old 03-25-2018, 07:01:13 AM
Wayne 440 Wayne 440 is offline
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Default Re: Onan 7.5 JB 3CR/2442T Added to the Fleet

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Originally Posted by 51f1 View Post
I'm thinking about putting my 7.5 LPG fueled model on a Harbor Freight wagon. HF says it will hold 1,000 pounds, which I doubt...
If it is this one https://www.harborfreight.com/steel-...gon-38137.html or anything similar, I would not put a JB on it. To me, it is a tip over waiting to happen. The narrow track and high center of gravity make it suitable only for level, smooth floors and even then you have to be very careful.
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