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Allis 720 (powermax) Heat shield


rickf

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Hi

Hoping to replace the mechanical fuel pump on my onan this weekend, was running fine, but depositing oil on top of the block. (do the electric fuel pumps run full time with the return line in place? - seems like there would be no resistance to shut it of intermittently.)

Anyway scouring the archives and the web for pictures I noticed several onans (cckb) that have heat shields on top. Mine did not come with one, but it seems like there are also plenty of pictures with them missing or not present. I don't see the part in the onan manual, but it is in the simplicity manual, (#176374). And I only have the Allis service manual, not the parts manual. Were these part of the original Allis setup? I can't say my carb has felt overly hot after using the tractor for a while, but still probably a good idea to keep the heat out. Any thoughts? Should I fab my own, or do these show up on ebay occasionally?

Thanks.

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The heat shield is from the factory. The mounting tabs crack and/or break at the manifold mounts or get removed to make working on the carb, fuel pump,etc, easier. I fabricated one. I have the drawings on digits somewhere.

picks 008.jpg

picks 009.jpg

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I wondered what the mounts in the manifold were for. If you have the drawings wo a lot of heartache to dig up, I'd love to 'borrow' them. made a heat rear shield for a vermont castings wood stove last fall, have the spare metal, and heat resistant black paint already...Thanks.

quote:Originally posted by AcFordHawk

The heat shield is from the factory. The mounting tabs crack and/or break at the manifold mounts or get removed to make working on the carb, fuel pump,etc, easier. I fabricated one. I have the drawings on digits somewhere.


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Looks like most folks have put them in in that fashion, though I see reports also of ditching the return line. I sort of assumed electric pumps weren't designed to run full time, (my experience with older cars) no worries with them running full out of premature wear? - of course the tractor probably sees minimal hours over the course of a year compared to a car...

quote:Originally posted by MPH

Yes, the electric fuel pumps run full time with a return line.


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I used a Onan electric electric pump on my 620 and kept the return line. The pump starts fast at first and slows to a slow click when running and in a 6 or 7 hour day of tilling it only shuts of for fueling.

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I've got the small Facet electric pump on my 720 without a return line.

It only generates 1-3 lbs pressure and works great on these engines.

Napa doesn't handle them anymore so skip them. Try Kirk Engines performance. He sells the correct one

www.kirkengines.com

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Paul was kind enough to forward his template for the heat shield - though it seems like most onan pics on the web seem to have it missing. Anyway, I converted it to a PDF should be the actual size, and a tiled version you can print off and tape together... Check the size when you print it though!

hmm looks like I can't attach pdf's here - anyone I can send them to to store on the site somewhere?

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