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Had friend ask me about the Yamaha engine. Could not tell him anything about it since I have never seen one on a mower. Thought you guys could give me some feed back. Pros and cons in and out durability support ect. Thanks for any thing you might know about them. Says he can get one at a really good price.

Tell your friend to stay away from the Yamaha V-Twin engine. I had a bad experience with one that came on a Gravely Pro Turn 160. It never held a steady idle speed. It seemed to cut out at higher engine speeds( RPM fluctuations). It would cut off after running hard for about 45 minutes. Vented gas caps installed. Carburetor rebuilt. Three trips back to the dealer. Carbon fouled plugs. Oil on plug threads. Left hand plug would get loose in head. It had high fuel consumption. The dealer gave me full price paid on trade for a Pro Turn 260 with Kohler. Gravely doesn’t even list the Yamaha engines in their 2022 catalog. Stay Away!
Made in China. Heck the Chinese made Loncins on Exmark and Toro are better engines.

I've only had experience with Yamaha horizontals, I would put them up there with Honda and Kawasaki. J.A. Pan, of course.

Scrubcadet10 said:

I've only had experience with Yamaha horizontals, I would put them up there with Honda and Kawasaki. J.A. Pan, of course.

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Go to the Gravely, Bad Boy, and Yamaha engine part of the Forum and you will see the problems people are experiencing. Bad Boy no longer offers the Yamaha engines. Gravely doesn’t list them in this years catalog. I contacted Gravely to ask about that. The reply was sourcing and supply chain BS. Deep down, I believe that there are other reasons.

A couple of more things.
The Yamaha uses a 65 degree V-Twin design.
Yamaha uses a hemispherical head design with 3 valves per cylinder.
Valve adjustment is a bit different. Yamaha uses shim pads to adjust valve lash.

@hlw49 There could be a very good reason that your friend can get a good deal on a Yamaha engine. Or, a very bad reason.

hlw49 said:

Had friend ask me about the Yamaha engine. Could not tell him anything about it since I have never seen one on a mower. Thought you guys could give me some feed back. Pros and cons in and out durability support ect. Thanks for any thing you might know about them. Says he can get one at a really good price

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hlw49 said:

I you are looking at Zero Turn machines find something with an upgraded air filter system. Machines with engines like the Kawasaski FR series with the small air filter right on the back of the engine are good for nothing but cleaning air filters. r

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@RayMcD
What does the upgraded air filtration system have to do with the original question?

Nothing but is it important
Most air filters on mowers are poor at the best so you should look at that when making the purchase decision
Damaged bores by bad filters come in a close second to too little oil as a terminal engine fault , particularly with a ZTR that is bagging .

bertsmobile1 said:

Nothing but is it important
Most air filters on mowers are poor at the best so you should look at that when making the purchase decision
Damaged bores by bad filters come in a close second to too little oil as a terminal engine fault , particularly with a ZTR that is bagging .

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The particular Yamaha powered Gravely PT 160, that I owned, came standard with the Donaldson double air filter.

MParr said:

The particular Yamaha powered Gravely PT 160, that I owned, came standard with the Donaldson double air filter.

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SO you got one of those Monday morning hangover specials
All the right gear wrongly put together .

bertsmobile1 said:

SO you got one of those Monday morning hangover specials
All the right gear wrongly put together .

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I don’t know on which day it was made. But, I should have dug a little deeper before buying one with the Yamaha engine. There are plenty of examples of Bad Boy mowers having problems with the Yamaha power plant. The Kohler on my new Gravely is one sweet running engine.

Funny
I just did a Toro Titan & had to drill out the main jets to stop it running way too lean
This is the 3rd time I have needed to do this
Owner said it has never run as well from the day he bought it .
Engine was overheating because it was running so lean and if it was stopped for more than a minute or so would not crank
Fine if the mowed the 20 acres in one hit but if they had a toilet stop, that was it till the engine became stone cold .
And sure enough, when trying to start a hot engine the starter could barely turn the engine over

bertsmobile1 said:

Funny
I just did a Toro Titan & had to drill out the main jets to stop it running way too lean
This is the 3rd time I have needed to do this
Owner said it has never run as well from the day he bought it .
Engine was overheating because it was running so lean and if it was stopped for more than a minute or so would not crank
Fine if the mowed the 20 acres in one hit but if they had a toilet stop, that was it till the engine became stone cold .
And sure enough, when trying to start a hot engine the starter could barely turn the engine over

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Was this a Loncin or Kohler?
I would definitely choose a Loncin over a Yamaha.

7000 series Kohler

bertsmobile1 said:

7000 series Kohler

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I wished that would have been all that was wrong with that Yamaha. The rebuild and updated float would have fixed it. There was a service bulletin and updated float for the carburetor. The next time I get by my Gravely dealer, I’ll see what they found. I imagine that Gravely sent them a new Yamaha engine and they either sold the mower or used it for a loaner. Gravely wouldn’t allow the dealer to repower with a Kohler or Kawasaki. The mower model and serial numbers would have to match with a Yamaha engine.

MParr said:

I wished that would have been all that was wrong with that Yamaha. The rebuild and updated float would have fixed it. There was a service bulletin and updated float for the carburetor. The next time I get by my Gravely dealer, I’ll see what they found. I imagine that Gravely sent them a new Yamaha engine and they either sold the mower or used it for a loaner. Gravely wouldn’t allow the dealer to repower with a Kohler or Kawasaki. The mower model and serial numbers would have to match with a Yamaha engine.

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I stopped by my Gravely dealer today to pick up some transmission filters for the ZT 5400 hydros and look at some pole saws. I asked one of the owners about the Yamaha powered Pro Turn that I traded in. He informed me that Gravely and Yamaha authorized an engine replacement. He said the MX800V replacement engine wasn’t a whole lot better than the original. He said, they keep the mower around the shop for various things.

I was at my Gravely dealer buying service parts, yesterday. I asked the owner about my former Pro Turn 160. He said that, he had it at his house and it was running fine for three hours. My last visit, he said it was on it’s second Yamaha engine and that one was running bad. He finally told me that he recently installed the second warrantied engine. So the darn thing is on it’s third Yamaha MX800V engine in two years. Don’t let friends buy Yamaha powered mowers.