[Henry_Gunn]

I purchased a used promaster 50 with a k341 engine. It was running fine, cut the lawn and headed to the garage and the engine shut down. It will crank but will not fire. After letting off the crank the engine seems to continue spinning freely. Any idea where to start looking?

When cranking I don't feel air coming out the exhaust.

 

[Fla Don]

I think that model still had the compression release. It will act like a stuck exhaust valve.

 

[audinutt]

Have you verified that you have spark?
Did the engine make any odd noises or knocking prior to this condition?
It sounds like either you threw a rod or a valve is stuck open. either way I'm betting you'll have to pull the head.

It could be the Automatic Compression release feature.
Here is the link to your engine's service manual. It sounds like you'll need it.
Section 9 is about the Automatic Compression release, it may be what you need to check first.

http://oldgravelys.net/pdf/Kohler_K91_K141_K161_K181_K241_K301_K321_K341_Serv_Man_1192.pdf

Keep us posted,
-Richard

 

[Henry_Gunn]

Thanks for comments. I will look into the idea you both mentioned and report back findings.

 

[rscurtis]

I doubt it's the ACR. Even if it's stuck, the engine should still have enough compression to run, and you would feel something coming out the exhaust. I vote for a more serious problem.

 

[DJ in WV]

I would have to agree. With no air movement in or out of the exhaust, and very little resistance to crank spin, as in "freewheeling", it really sounds like a broken rod.

 

[Henry_Gunn]

All,

I pulled the head and the piston did not move. Pulled engine from the tractor and opened up the oil pan.... it is ugly. It looks as if the crank has some remnants of the rod. Can this be cleaned off or will I need to get it turned?
Will any K341 crank work or are the made specifically for Gravely? I see some on the ebay for a Deere.

 

[Richard-tx]

From the looks of it, I would say that engine has been worked on before. The 010 in paint tells me someone already turned the crank down by .010. Based on that evidence alone, I would say to get a crankshaft. I also believe that this is the second major failure that engine has seen and in the same area. I cannot see the detail of the crank journal, but my feeling is that it is damaged beyond repair anyway.

If it were mine I would get a new crank, rings, connecting rod and maybe a new piston too.

 

[Jimmy in NC]

Unfortunately the cranks are specific to Gravely (I'm 99% sure of this one) which is why replacement engines are so expensive new. The good thing is you have a great resource here and the same engine was used on many of the 4 wheel riders. You have options as to which engine you would like to put in at this point or if you simply want to purchase the crank, etc and rebuild. Cranks may still be available new too, but they will be pretty spendy from what I have seen.

There is someone that rebuilds Gravely Kohlers that may have what you need. I can't remember his name and I do not have his contact info. I'm sure someone will chime in if he doesn't mind it being spread publicly and they may even know if he will sell parts if you are looking some.

 

[Mickeymotormount]

Henry, you can use Muriatic acid to remove the aluminum from the crank journal. There are several posts here describing the use of it to remove it. I would read these posts to give you a little insight on the task at hand. Once the journal is clean, I would measure it to be sure it's within specs and not out-of-round.

I would recommend removing the crank from the block to handle this task. It also opens up the block for investigation for damage and cleaning. Check the bore to see if it's not worn to the point of a bore job. You may luck out and need only a rod and piston. Keep us informed and don't be afraid to ask questions. Good Luck.

http://www.mytractorforum.com/showthread.php?t=152642
http://www.mytractorforum.com/showthread.php?t=100765&highlight=muriatic+acid

 

[Fla Don]

Unfortunately the cranks are specific to Gravely (I'm 99% sure of this one) which is why replacement engines are so expensive new. The good thing is you have a great resource here and the same engine was used on many of the 4 wheel riders. You have options as to which engine you would like to put in at this point or if you simply want to purchase the crank, etc and rebuild. Cranks may still be available new too, but they will be pretty spendy from what I have seen.

There is someone that rebuilds Gravely Kohlers that may have what you need. I can't remember his name and I do not have his contact info. I'm sure someone will chime in if he doesn't mind it being spread publicly and they may even know if he will sell parts if you are looking some.

The crank is Gravely specific. About $420 plus shipping new.

The Kohler person for Gravelys is Robin A. Snyder in Carmichaels, PA. A Gravely TCofA member.

 

[Richard-tx]

I think one of the more important questions is to ask why. Why did the rod self destruct? What is the root cause? It doesn't do any good to fix it if the root cause isn't addressed.

 

[Fla Don]

Unlike a 16HP twin, the total torque on the single comes at one point in the cycle and they are not pressure lubed. Those two things work against the engine. That same torque problem is also why the PM-50s were hard on the High-Low planetaries. Check them for wear while the engine is off.

 

[gravelymay]

This a good spot to re power.
Use Gravely 46410 gear and Gravely 46411 pilot bushing
You can use a Kohler or any other engine with a 1 inch crank shaft.

 

[Henry_Gunn]

This a good spot to re power.
Use Gravely 46410 gear and Gravely 46411 pilot bushing
You can use a Kohler or any other engine with a 1 inch crank shaft.

What is the engine that is shown in your pictures?

 

[gravelyman66]

it looks like its a honda repower but might be a vanguard

 

[gravelymay]

That particular picture is a Honda.
But Here are some more different engines
a 13.5 Robin
and here is a C10 Kohler same bolt pattern just different crank
Next is a spacer adapter you can use for the extra crank length
Make the thickness for crank length.
A 10 hp Diesel
:thThumbsU

 

[gravelymay]

That particular picture is a Honda.
But Here are some more different engines
a 13.5 Robin
and here is a C10 Kohler same bolt pattern just different crank
Next is a spacer adapter you can use for the extra crank length
Make the thickness for crank length.
A 10 hp Diesel
:thThumbsU

With this method you can put up to 20 Hp on the Promaster
The transmission may be stressed.
or anything that has a 1 inch crank and same bolt pattern. :trink39:

 

[Henry_Gunn]

With this method you can put up to 20 Hp on the Promaster
The transmission may be stressed.
or anything that has a 1 inch crank and same bolt pattern. :trink39:

Bolt Pattern...?? Is there a common bolt pattern for engines? I found what I think is a honda clone at HF - blue color. Do you think this engine has the same bolt pattern? Would my current adapter from the K341 bolt directly to a Honda without modification?

Earlier it was mentioned about the 1" shaft gears and it was mentioned about a spacer. It looks like the spacer is made from billet alum. Who can I get them from or do I need to find a local machine shop to make one?

 

[Fla Don]

Bolt Pattern...?? Is there a common bolt pattern for engines? I found what I think is a honda clone at HF - blue color. Do you think this engine has the same bolt pattern? Would my current adapter from the K341 bolt directly to a Honda without modification?

Earlier it was mentioned about the 1" shaft gears and it was mentioned about a spacer. It looks like the spacer is made from billet alum. Who can I get them from or do I need to find a local machine shop to make one?

gravelymay makes his own.