Plastic vs. Walbro carburetors

viperv10

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Hi fellows, I haven't been on here for a long time and it looks pretty dead on the forum. I just had an idea and I thought it might get something going on here.
Have any of you guys ever tried to swap out a metal carburetor for a plastic one? I don't know if they will even fit or not. I just ordered an extra Walbro on ebay and was just thinking I may try putting it on an old 1980 F100 series engine that has a plastic carb. The plastic mounting surface is just a little bit warped but not bad. I have 2 gaskets on it and it seems to seal up fine. Does anybody have any thoughts or ideas on this matter? Thanks.
Jerry
 

jp1961

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Hi Jerry,

Yeah, it's been real dead on the L.B. forum.

I don't see why it wouldn't work, as long as the bolt spacing is the same. Also the air vane governor would have to be similar too.

I've swapped out diaphram type carbs on weed whacker engines successfully.

It's been a fairly productive winter for me, I touched up the deck on my Lawn-Boy 10547, put new piston rings and seals in my Troy-Bilt tiller and also put new rings and seals in my Honda walk behind mower.


Regards

Jeff
 
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2smoked

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Viper, I have always had that same carb question in the back of my mind. I’ll be curious to know if a swap does work out. Personally, I have never had a problem with the plastic carbs, but just like anything else, they do eventually wear out.

As far as the deadness on this forum, I think that it’s just an indication of the deadness of this winter. Thanks for getting things going again! Up hear in Wisconsin, February has been colder than average and the ground is frozen very deep yet. Oh, how I look forward to green grass and another season of hunting up old Lawn Boys!
 

javjacob

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I actually prefer the plastic carbs. They are less problematic and are easier to work on. Seat and needle changes on the plastic carbs are very easy to do.
 

Lawnboy77

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Going from a first gen F series with the old OMC plastic carbs to the newer Walbro carb requires a pulse hole to be drilled in the carb mating flange of the old OMC cylinder cover. It's a tight fit for sure, not much room for error on the drilling of that hole so I would not recommend it if you don't have equipment to make an accurate hole. As best I can tell that pulse hole is just used for cold starting where the throttle plate is wide open, once you go just below WOT the hole becomes restricted by the shaft hole not lining up with the hole in the flange, hope this makes sense. Of course there will be other considerations as well if you are working with a machine that is precompliance, such as throttle cables, where non existed with the old F series. It's much easier converting the later 90s version to metal since it's pretty much a bolt on change with just a carb and throttle cable swap for the most part.
 

jp1961

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Hmmm, I thought pulse ports were just used on diaphragm type carbs to work the diaphragm which activates the fuel pump portion of the carb?

Anyhow, I've got a Bridgeport in my basement and would be willing to drill the hole for Jerry.

Regards

Jeff
 

viperv10

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Ok, thanks guys. That's what I wanted was some thoughts. It was just a hair brain idea I had.
I can't believe the weather we have been having. It rained everyday last week and the last two days it has been 55 and sunny. Not bad for Feb.
Thanks again for the replies. Got to get back to the salt mine.
Jerry
 
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