Will this work? (engine swap question)

[alewood97]

I have a 36" Toro walk behind belt drive model #30253 with a Kohler 15hp cv15t engine. The engine sucked in a choke blade screw and ate it. The mower chattered for about 15-20-seconds and I never heard any noise again. I asked a local dealer what to make of this and was advised that the screw was probably sitting on top of the piston and causing no harm. I bought a replacement screw kit, installed it and went along my way. Several months later the engine began to smoke and consume oil. I suspect that screw probably bounced around scratching and scarring the cylinder til the ring wore out. Engine still runs strong just consumes about a quart of oil every 5-6 hrs and has developed a tick. At the time I had no back up and no time or money for rentals or downtime. So i had to press on and hope the machine made it into the off season which is where I am at now. A buddy of mine recently gave me an mtd yard machine tractor with a Briggs & Stratton 17hp intek v twin model #42a707 that was hit by one of his employees. The axles and frame were damaged but the engine is good.

Here are my questions.
1. Is there any hope for the kohler?
is it worth trying to rebuild?

2.Can I swap the B&S onto the Toro frame?
is there any difference in tractor engines vs w/b engines? Both are verticle yes?

3. If so would it be hard to wire up the electric start from the tractor onto the walk behind. The Kohler was a pull start.

4.What are your suggestions?

Thanks all

[Jay Ray]

I would think the Kohler would at the least have to be bored oversize and re-ringed, probably new piston too. Head might have problems, I don't know. Lot to put into an older engine.

More than likely the crankshaft stubs are the same size on both engines. The Briggs probably has an alternator that will operate the Toro electric blade clutch, and the engine will likely bolt right in. It is most likely doable but you will have to build a battery box onto the mower somewhere and solve the electrical puzzles of what wire goes where.

If the Briggs has the fuel pump that is practically built right into the carb you will have to use it I think, even though the gravity fuel feed alone would do fine

If the Briggs has the dual alternator, AC and DC, I think the AC is just for the headlights on the LT and you would not use it on the wb. Just tape up those wires.

Also if the exhaust drops off the front of the LT frame like MTD is apt to do, you may have to re-route the piping and perhaps use a different muffler or even two pepper can mufflers (cheap).

If your buddy has the parts manual that has the electrical schematic for the MTD LT better get that from him. Should help.

There are lots of guys more knowledgable than me on here and I hope they will weigh in, but this should get you started thinking.

[topsites]

A lawn mower can be powered by any brand engine, so long the specifications match.

Kohler is a brand name, so is Briggs, you can put a Honda or a Kawasaki on there just fine,
I've put two Briggs engines on two different Toros before, it works just fine.

But you need to know if the shaft size and specs are the same, things such as keyed vs. un-keyed,
what you want to do is look up the model number of that Briggs and see if you can find what
applications it is made for.
Then look up the Kohler's model and compare the spec sheets side by side.
Shaft size is most important, however so is the starter system (ES vs. recoil).
This should also answer the question concerning a tractor engine, but I think you're ok there.

And as a rule, it's cheaper to replace than rebuild, probably more so if you've never rebuilt one before.
Keep it thou, either rebuild it as a learning project, but ALWAYS keep broken equipment for parts!

[alewood97]

Thank you both. This is very helpful information. I think the shaft specs are the same for both. I will double check though. I have another junk briggs vangaurd twin 18hp that's locked up that was also given to me that looks to be the same size that I think i can take the exhaust from as it is dual into one peppercan muffler. I haven't measured yet but the exhaust port configurations look the same. The hard part will probably be figuring out the electronics and fuel delivery as you all have stated. Bottom line though, is it looks and sounds doable. Just needed a little reassurance.

PS:I never pitch anything cause you never know when it will come in handy.
One mans junk is another mans treasure!

Thanks all

[Bill Kapaun]

I'm really not familiar with your mowere and how it's set up, but-
Will the Briggs opposed twin actually fit?
Does your mower have an electric PTO. If yes, make sure the Briggs has the proper charging system else you would have to change it. That cost would negate a lot of the advantages.
Does the Briggs have a voltage regulator, or just 1-2 wires (probably red and/or black) coming from the stator? If the later, it only has a nominal 3-5A DC charging circuit. Not really enough to operate an electric PTO & charge a battery..