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I have a Onan B48 on my 818T. It is not getting fuel. The tractor runs fine when I fill the carb. I put a new valve on the carb because the old one was cracked at the inlet. It still isn't getting fuel. The when I take the fuel pump off it does have some fuel in it and the bottom of the "bowl" has some also. Any ideas? Also, the float looks like it is made form foam. Should that be replaced? The fuel that is getting into the carb is not enough to move the float so I do not think that is my problem.
Thanks for any help.
 

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I have a 818T myself. I would say that the problem is NOT with the float. Maladjustments aside, a bad float will cause flooding, not fuel starvation.

I would check the fuel line for cracks. A quick test would be to take a new piece of fuel line and connect it to the carb and stick the other end in a gas can. I would check for proper flow from the tank. With a full tank of gas, fuel should flow freely from the line near the engine.

It is possible that the integral fuel pump has failed. There are rebuild kits for the Marvel carb that includes the fuel pump diaphragms.

It is interesting that you have an epoxy float. Mine has a brass float - not that it matters. The epoxy that Marvel uses for floats is good stuff. It has to be since their carbs are used on airplanes. A failure of a float could spell disaster. See the video at http://www.msacarbs.com/
 

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Deere 330 Killer
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Heres a trick, works on DD carb pumps. Take the pump apart and put oil on the gaskets, seals it up and makes it pump like new.

Installing a brass float (can be had on ebay for ~30 bucks) solves a lot of future problems
 

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Gravely bug bit.
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I have a 818T myself. I would say that the problem is NOT with the float. Maladjustments aside, a bad float will cause flooding, not fuel starvation.

I would check the fuel line for cracks. A quick test would be to take a new piece of fuel line and connect it to the carb and stick the other end in a gas can. I would check for proper flow from the tank. With a full tank of gas, fuel should flow freely from the line near the engine.

It is possible that the integral fuel pump has failed. There are rebuild kits for the Marvel carb that includes the fuel pump diaphragms.

It is interesting that you have an epoxy float. Mine has a brass float - not that it matters. The epoxy that Marvel uses for floats is good stuff. It has to be since their carbs are used on airplanes. A failure of a float could spell disaster. See the video at http://www.msacarbs.com/
Many Onan floats have failed. It is recommended to replace them with the brass ones when they get old.
 

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I just bought a new brass float for my DD carb just last week. The original was recently damaged (don't ask...it was stupid) and repaired so I bought a new one.
 

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richard
i SURE hope that you pur. a REAL onan o.e.m.brass float.
thank you. boomer (the used onan engine prts guy)
I just pulled it out of the package. It looks good to me. It looks identical to the float that was in there.

Are there inferior clones out there?
 

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richard
in my opinion all the after market are inferior.
if you have the REAL one it will come with a buoyancy.
spring.
on one of the clubs today, there was a DD with a clone
that the owner had to remove the needle clip to get it to work properly.
i have heard of many fitment problems, on these floats.
WE all know where they are made.
p/s if you have an extra buoyancy spring i would like to pur. it.
thank you boomer (the used onan engine parts guy
 

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I ordered one of unknown origin and a Onan OEM. I will compare the two when I get OEM in my hands.

richard
 

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Boomer,

I will do as much as I possibly can to document the differences if any. I have a fairly accurate scale and a few good micrometers. If will post the results of my tests in another thread.
 
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