Lawn Boy motor on a kart threads here

[Russ2251]

My very first conversion was a 'D' engine from a 1980 model #8601. Now that I see it again, it looks kinda goofy.
Problem was exhaust port.
Muffler is connected to engine (with gasket and support flange) when bolted down to mower deck.
No easy way that I know of to secure muffler (or pipe of any kind) to engine.
Remove one of these engines from it's deck and you'll see the problem.
Engine was mounted to kart but never saw a test run. Noise pouring directly out of exhaust port was a bit much (even for me). Even a straight pipe tones it down to tolerable levels.
'D' engine Kart:

 

[Spule 4]

Interesting. I have two D mowers that both run (my 19" 1983, last year of the D did not when I got it funny story) and have never been apart and a Utility motor like yours that needs starter work and a deck (or a Kart?). So I have never had to take one apart to notice the muffler aspect.

What kind of performance did you get out of the D kart?

The 1983 model is super clean. I got it for $10 with some other LB stuff from a shop that could never get it running. It had a bad kill wire, and I had it running in a matter of minutes. Fun little mower.

Digging in the crawlspace I found some 1970s JC Penny Lawn Boy parts for a F shroud with seprate tank that would be perfect for a kart motor. And all my electric start bits.

This is looking more and more doable and interesting!

 

[Russ2251]

What kind of performance did you get out of the D kart?

Was never tested.

 

[Spule 4]

Shame. Could have been a fast rever if a bit slow at top end.

Boy I hate the 5hp Briggs on my kart, every time you fix one bit, another breaks......

 

[Russ2251]

every time you fix one bit, another breaks.....

4 cycle = more stuff to break.

 

[Spule 4]

4 cycle = more stuff to break.

True, but honestly, it is STUPID stuff. Butterfly comes off of the throttle (ran wide open) but somehow it and the screw were still in the intake.

Fixed that today (sort of, throttle shaft is SHOT, almost hour glass shaped) and then when starting it, I found the entire starting rope in my hands......

 

[jr dragster T]

Yeah well you cant blame a carb butterfly falling off because its a 4 stroke brigg's. Most likley you didnt have the WOT throttle stop set right and it over pulled it and snapped it off. BTW I ripped the starter cord off the Tecumseh 12 hp at work today lol.

 

[Russ2251]

Could be throttle shaft is worn/binding causing misalignment of butterfly in throttle bore. Could be causing it to flex/bend to the point that it breaks off.

 

[Spule 4]

Actually, nothing broken, just the butterfly screw worked loose, all back together now. Fun getting it back in down that LONG throat, involved a sharpened chopstick and a pair of hemostats to get it back together.

But the shaft is still worn, and most likely this is causing havoc with the air/fuel mix for sure. I have had to fight this before with SU carbs on cars. On those, I would get them rebushed.

One last question since I really do not know Briggs... Is there a seal or the like in the top of the pulse-jet carb body where the shaft enters? There is a round depression in there, about 2mm bigger than the shaft entry itself.

Thanks again guys.

 

[Kenny_McCormic]

My very first conversion was a 'D' engine from a 1980 model #8601. Now that I see it again, it looks kinda goofy.
Problem was exhaust port.
Muffler is connected to engine (with gasket and support flange) when bolted down to mower deck.
No easy way that I know of to secure muffler (or pipe of any kind) to engine.
Remove one of these engines from it's deck and you'll see the problem.
Engine was mounted to kart but never saw a test run. Noise pouring directly out of exhaust port was a bit much (even for me). Even a straight pipe tones it down to tolerable levels.
'D' engine Kart:

Larger mounting plate (to cover exhaust port) with a header welded on?