1989 L250 Engine replacement suggestions

[loumar]

Hi Everyone,

I have an older L250 with a tired Onan B43G engine and I was thinking of replacing it. Anyone have any good suggestions for a replacement? Been trying to find something that could work but most of them have the exhaust on the shaft side which i dont think will work out for me. I can probably try and add additional pipe to try and reroute it but wasn't sure if the would impact any performance. Also since the shaft is behind the drivers seat, would that mean the engine spins counter clockwise?

Thanks for any help

 

[tech.35058]

Greetings loumar.

https://www.engine-specs.net/onan/b43g.html describes your B43G as a 2 cylinder flat air cooled engine, "pto shaft rotation clock wise as viewed from the flywheel" . ( this is standard rotation, I I believe. But, just to be clear, since most small air cooled engines incorporate the cooling fan & flywheel on the opposite end of the engine from the pto shaft, you might want to verify this.
I recently replaced the kohler V-twin engine on my daughters Toro lawn mower. This particular machine drives the blades from a belt on the main PTO shaft, facing the rear of the machine, and the drive pumps via an "add on" stub shaft on the flywheel-fan end of the crankshaft. But, this did put the exhaust & muffler on the back end of the machine, away from the operator.
In this particular case, the original engine was mis-identified since some one had swapped the air shrouds previously, but the replacement engine had also been mis identified, I think. ( I had to pull the shrouds & repair some wires, and retain my "old" carburetor.) In the end it worked out, but it was not the simple engine swap I had anticipated.
If you are comfortable working inside the engine, you might consider reworking the engine you have, versus all the surprises that come with a "not precise part number" replacement.
Which ever route you take, good luck!

 

[loumar]

Hey tech.35058,

Thanks for that information. I just ordered a service manual for the engine. I think i will take it out and tear it down first. I read that the heads needs to be cleaned every 200 hours and from the way its mounted and limited spacing, i doubt anyone ever did that.

 

[loumar]

Hi tech.35058,

Thanks for replying back, greatly appreciate the info. I just ordered a service manual for that engine. I think i will take a shot at removing it and giving it a once over. I read that the cylinder heads are supposed to be cleaned every 200 hours. From the limited spacing in the bay area, i doubt the previous owners ever done that. I dont know how many hours on it exactly as the meter hasnt worked since i purchased it. I'll go that route first and see where it gets me first. I was hoping for a somewhat easy replacement without paying around 2000 like i have seen on some replacement engine sites.

thanks