Swapping an 800 carb to an 801 tractor

[Jim L]

I'm running an 861 powermaster tractor now and was wanting to know if I switch carbs from an 800, will the 801 be running too lean with the smaller 800 carb? The 861 runs great, but it's a little hard on gas. All I run in it is non-ethanol gas. I figure the motor will loose some hp, but it has plenty to spare. I always thought the 172 engines were the same except for the manifold and exhaust. if I were to do the switch,I just don't want to burn any pistons from running lean. I don't know how much better the 800 is on gas, but have heard they were a little better.

 

[BethelHntr]

You could always keep an eye on the spark plugs for color if you decide to switch carbs, A nice tan/brown would be optimum plug color.

one could probably find the jet size's for both carbs online before the switch is made, Might tell you if you'll save any fuel or not.

 

[Jim L]

Hadn't thought of that. Right now with the carb that's on it, the plugs tend to run black and slightly wet. It's got a cheap set of points in it now. I have a good set of Standard brand points and condenser I've squirreled away,I might have to install on them. Got to thinking about the flanges where the carbs mount. If I remember correctly, the 801 flange is slightly wider than the 800 one. May not be able to fit the 800 carb on the 801 intake. Guess I need to get down to the shed and do some measuring The 800 carb is a TSX 700. The 801 is a TSX800? Not sure... EDIT...I went outside and checked the carb on the 801. Turns out it's a TSX662. Measured the spacing on the carbs and the 801 carb measures 2 5/8 center to center on the mounting bolts and the 800 carb is 2 3/8. The intake don't allow for a smaller flanged carb to fit without some "modification." The 801 carb...

 

[BethelHntr]

Yeah if they don't share the same bolt pattern that option is nil, Heavy fuel consumption could be traced to the choke being partially closed while operating, Make sure the choke opens fully when choke cable is pushed in, A vacuum leak at the base of the carb or intake manifold, Make sure all carb base nuts are tight (don't use bolts to fasten carbs, Always use studs with nuts) and check intake nuts or bolts.........

 

[Jim L]

Thanks I've checked the vacuum pressure and it runs steady. Choke pushes in all the way. I guess this baby just likes the sauce LOL. I'll just get an extra 5 gal of gas when I use it. I know this 861 has a lot more power and torque than my 660 so I guess you gotta pay the price for the power.

 

[Soundguy]

Yeah if they don't share the same bolt pattern that option is nil, Heavy fuel consumption could be traced to the choke being partially closed while operating, Make sure the choke opens fully when choke cable is pushed in, A vacuum leak at the base of the carb or intake manifold, Make sure all carb base nuts are tight (don't use bolts to fasten carbs, Always use studs with nuts) and check intake nuts or bolts.........

NIL?


ptah!


You can certaintly swap carbs around. slotted ears helps.

I have a NAA carb on my 950 right now. A little custom tweaking and it's running fine.

I certaintly wasnt needing all 172 cubes to run a 5' mower.. so why feed all those horses!

 

[Soundguy]

I'm running an 861 powermaster tractor now and was wanting to know if I switch carbs from an 800, will the 801 be running too lean with the smaller 800 carb? The 861 runs great, but it's a little hard on gas. All I run in it is non-ethanol gas. I figure the motor will loose some hp, but it has plenty to spare. I always thought the 172 engines were the same except for the manifold and exhaust. if I were to do the switch,I just don't want to burn any pistons from running lean. I don't know how much better the 800 is on gas, but have heard they were a little better.

short answer.... you can run a 134 carb on a 172 with a bit of tweaking.

new manifolds are universal fit with slotted ears.

old manifolds make you get creative with a drill or bastard file.

 

[Jim L]

Yeah soundguy, my 660 has a newer replacement manifold on it with the slotted ears. If I go ahead with the switch, I thought about an adapter plate. I'd kinda hate to a file to the bastard

 

[Soundguy]

files super easy... super super easy..

 

[Jim L]

Sound guy, would it be worth the trouble to switch for the fuel economy I'd get?