What if your engine needed replacing?

[smartguyz]

I was just wondering. I was reading a story about someone's garden tractor engine blowing up (incidentally, it was a Kohler 25 HP twin, same as in my PT425 - the article claimed that Kohler had skimped on the number and type of bolts holding the cylinder head on, and that as a result the head gasket would blow out and wipe out the engine).

Anyway, it got me thinking. If my engine died, what would I replace it with?

So, what would you guys do?

-Rob

 

[magicheater]

I would be tempted to do this. Don't know all that would be involved
but love those Kubota diesels!

 

[MossRoad]

I was just wondering. I was reading a story about someone's garden tractor engine blowing up (incidentally, it was a Kohler 25 HP twin, same as in my PO425 - the article claimed that Kohler had skimped on the number and type of bolts holding the cylinder head on, and that as a result the head gasket would blow out and wipe out the engine).

Anyway, it got me thinking. If my engine died, what would I replace it with?

So, what would you guys do?

-Rob

I'd probably replace it with the exact same engine. Unless I could find one of larger HP that was the exact same dimensions, then I would go with that. The reasons:

There are too many things to have to modify to get some other engine to fit. You could get a direct replacement and probably swap it out on a Saturday. Use any other engine and you will be down, down, down for days and days and days unless you have some fabrication background or are just gifted and talented! :laughing:

 

[Johndeere3720]

I would put another Yanmar engine in my tractor. I love Yanmar engines.

 

[RegL]

I'd replace my 28hp Deutz with a model 2011f 45hp. I checked it out once and I think it had about the same dimensions.

 

[pajoube]

I was just wondering. I was reading a story about someone's garden tractor engine blowing up (incidentally, it was a Kohler 25 HP twin, same as in my PT425 - the article claimed that Kohler had skimped on the number and type of bolts holding the cylinder head on, and that as a result the head gasket would blow out and wipe out the engine).

Anyway, it got me thinking. If my engine died, what would I replace it with?

So, what would you guys do?

-Rob

I did replace my Kohler 25hp with one of the same. Fast and simple.
PJ

 

[Clarke]

I was just wondering. I was reading a story about someone's garden tractor engine blowing up (incidentally, it was a Kohler 25 HP twin, same as in my PT425 - the article claimed that Kohler had skimped on the number and type of bolts holding the cylinder head on, and that as a result the head gasket would blow out and wipe out the engine).

Anyway, it got me thinking. If my engine died, what would I replace it with?

So, what would you guys do?

-Rob

I really doubt that. If you read the Kohler service bulletins you will find one with a fly wheel timing change from 22 to 16 degrees. The bull. states the 22 degree is what blows the head gasket. They have a new offset key or a new fly wheel to address this problem. I removed the engine from my 2004 model 425 and installed a new fly wheel hoping also it would cool my continuously over heated exhaust which melts the muffler. I think the engine runs a little better with the timing change but the exhaust system still gets to hot. Kohler tech. support says my engine is running to lean and I should replace the carb. which has already been replaced. I have fabricated a new stainless steel exhaust system for the machine with a Quiet Trap muffler mounted out side the cover. When running with the choke off the new stainless pipe runs cherry red. If I add a little choke the pipe cools enough it doesn't glow in regular light. The Kohler parts supplier tells me if I buy a new carb. as they suggest for near $300 if i'm not satisfied with the results that's to bad. Anyway I have given the engine change out some thought let me run this by you. With a new exhaust there is a lot of room under the hood on mine. Thinking of a Kohler 28HP liquid cooled. The engine will not fit as shipped but if the radiator is relocated and cooled with an electric fan I believe it will fit. If the high eff. air cleaner is retained I would have to raise the hood a little. Any thoughts.

sg

 

[Gravy]

Clarke,

I really doubt that you need a whole new carb. It sound like the main jet is either restricted or too small. There may be a larger jet available, either from the engine manufacturer or the carb manufacturer. Motorcycle shops often stock jet kits.

As a last resort, you could ream out the jet, but that can be tricky.

 

[smartguyz]

I agree with Gravy on this one. You typically don't need a whole new carb to adjust the output of the one you have. Drilling carburetor jets is a fine art, but if you have a set of finely graduated bits and a good steady drill press, it's worth a shot and doesn't cost the moon. You'll definitely have to have a set of extra jets on hand, find out how big the hole in the original jet is, and slowly increase the diameter. The tuner guys who build go-karts do it all the time, I understand.

There may also be the jets available from the newer carb. Assuming they are the same size (your parts dealer may be able to tell you) you can just swap them out. This would certainly save you the cost of a new carb. Assuming that all Kohler did was redesign the key components of the carb and not the whole design of the carb, this would be the easiest to do. You'd just buy what they call 'a rebuild kit' for the NEWER carb, and then install it.

If you've never rebuilt a carb before, you'll probably want a buddy to help you, as there tend to be lots of little parts, and you do need to keep track of where they all go. But, they are fairly straight-forward.

Mine is a 2003 PT425 with a Kohler engine (I bought it because of MossRoad's website and this forum - I kid you not) and it doesn't seem to run too hot. I do run Mobil 1 10W-30 in it, and check the oil and air filter before and after every run. I admit to changing the oil way more often than they ask for, I change it every year. Perhaps I should get a cylinder heat temp gauge (and a tach) to check things out.

Let us know what you do. As for the repower... I would likely just buy another Kohler, as MossRoad says, but am occasionally tempted to retrofit a diesel OR put in a Honda gas twin....

-Rob

 

[Clarke]

Individual components are not available for the carburetor due to EPA requirements. I haven't looked at the jet yet but was told it may be tamper proof. This is our government at work. A high altitude kit is available and several repair kits for fuel solenoid, acc. pump, float etc. are available.

sg