OHV Performance, No Governor

I see many posts about the flatheads, removing the governor and what needs to be upgraded. So if I remove the Governator, what else should be done? Does it have the same cast rod as the flatties?

Well its assumed that the OHV's have stronger rods throughout the tractor forums. No one really knows but Id believe it, it would make sense. The OHV engines are a lot more durable then a regular L shaped flatty in every way.

On any engine I remove the governor on I also take the sump off and take off the weights that are on the oil slinger. Doing this is a must. If I don't plan on removing the weights I wont even bother taking the governor off. The reason for that is because over time the oil slinger ( made of plastic ) gets brittle being submerged in oil and the tiny pieces of plastic that holds the weights on breaks, letting the weights fly around the engine. At this point there isn't really any problem other then the engine not running right, its when the weight gets caught under the "syncro-balancer" which has only about a quarter inch clearance from the bottom of the case that a problem occurs.

What usually happens is it punches a hole through the crank case and also breaks off the synco from the crank making the engine extremely unbalanced leading to a destructive detonation.


Covering the governor, there's a few things you could do to improve performance. Your going to want to tune the carbs high speed mixture because the engine will want too consume more fuel In the high revs when you have her screemin!

A new small engine K&N air filter will do good, and while your playing with the air flow a custom free flowing exhaust will likely be a good investment to the power house. Most engines have a thread able exhaust port. It takes a conduit pipe thread. Any House renovating/contractor store will have the pipe there. Make sure you change the fuel filter as well. There only a dollar or two.

By the sounds of it, this engine is OHV. So it wouldn't hurt to check the adjustment of both of the rocker arms  clearance to make sure its in spec.

Also a new high temperature spark plug wont hurt, a RCJ9 with a gap of .035.




If you want to go all out then your lookin into porting and polishing the intake and exhaust ports, decking the head, mid grade gas, copper head gasket, lapping the valves, a three angle valve job, a billet aluminum rod and flywheel, boring the cyl and getting an oversized piston, a bigger carb, and a bigger cam and valve springs. All of the other stuff should be done first though or else this stuff serves no use or improvement.

Yeah Im working on a flatty 12.5 check the link here its for my thread im working on that engine that came off a craftsman II keep an eye on it ill be updating it in a few weeks when i get some cashh

https://www.atltf.com/t2946-new-craftsman-ii-off-road-build

the54 wrote:

Well its assumed that the OHV's have stronger rods throughout the tractor forums. No one really knows but Id believe it, it would make sense. The OHV engines are a lot more durable then a regular L shaped flatty in every way.

On any engine I remove the governor on I also take the sump off and take off the weights that are on the oil slinger. Doing this is a must. If I don't plan on removing the weights I wont even bother taking the governor off. The reason for that is because over time the oil slinger ( made of plastic ) gets brittle being submerged in oil and the tiny pieces of plastic that holds the weights on breaks, letting the weights fly around the engine. At this point there isn't really any problem other then the engine not running right, its when the weight gets caught under the "syncro-balancer" which has only about a quarter inch clearance from the bottom of the case that a problem occurs.

What usually happens is it punches a hole through the crank case and also breaks off the synco from the crank making the engine extremely unbalanced leading to a destructive detonation.


Covering the governor, there's a few things you could do to improve performance. Your going to want to tune the carbs high speed mixture because the engine will want too consume more fuel In the high revs when you have her screemin!

A new small engine K&N air filter will do good, and while your playing with the air flow a custom free flowing exhaust will likely be a good investment to the power house. Most engines have a thread able exhaust port. It takes a conduit pipe thread. Any House renovating/contractor store will have the pipe there. Make sure you change the fuel filter as well. There only a dollar or two.

By the sounds of it, this engine is OHV. So it wouldn't hurt to check the adjustment of both of the rocker arms  clearance to make sure its in spec.

Also a new high temperature spark plug wont hurt, a RCJ9 with a gap of .035.



If you want to go all out then your lookin into porting and polishing the intake and exhaust ports, decking the head, mid grade gas, copper head gasket, lapping the valves, a three angle valve job, a billet aluminum rod and flywheel, boring the cyl and getting an oversized piston, a bigger carb, and a bigger cam and valve springs. All of the other stuff should be done first though or else this stuff serves no use or improvement.

Some pretty good notes there. Any time I do governor removal surgery, I too remove any of the governor internals that can be removed. In our vertical shaft splash lube engines, you cannot remove the governor gear itself, as it DOES serve as the oil slinger. So, you'd then do exactly what the54 writes above- remove the flyweights and retaining pins. You do not want these floating around in the crankcase.

Regarding the thread-in exhaust pipe, I'd just like to clarify- The thread in question is called NPT (National Pipe Taper) and is not only common in rigid threaded conduit, but also galvanized water pipe, and black gas pipe. Typically, single cylinder engines from about 8hp up, use a 1" NPT. The twins tend to be 3/4" NPT.

Please note that NPT sizes are a little weird. The "size" is a nominal inside diameter of the pipe and is quite generous. If you measure your port, it won't make much sense. A 3/4" NPT port will be 1"+ and the 1" NPT will be 1 1/4"+.

Thanks for clarifying that Doc. I've always been lucky making exhaust, and maybe a little lazy now that I think about it haha. I always take what I find around the garage that fits, then go to the store and use that as a reference. Never really had to measure anything yet but good to know how!!   

I really only know the technical end of the pipe stuff, because I did some natural gas piping in the past. But... Whatever works, eh?

Thanks. Good to know about the OHV engines. At some point I'm going to disassemble my block and find out where the leaking oil is coming from. While I do that, I'll remove the parts associated with the governor.

Kinda important to remember that NPT is tapered... this is what makes the pipe seal as it tightens. If ya put a nut on the end, it will fit loose... as you turn the nut down the thread, it will get progressively tighter.