Kaw FS691V on Ferris ZTR - sheared engine-to-frame bolts

[Probity]

I’ve got a IS700Z (52” deck) with Kaw. FS691V engine, bought in 2016, has ~500 hrs. on it now.

An odd (to me) thing happened yesterday. The 4 bolts that secure the engine to the Ferris ZTR frame - 3 of the bolts are sheared (with bolt stubs still in the threaded portion of the aluminum engine crankcase cover), and 1 bolt is completely missing (or was never originally installed?). Had this happened to any of you? Bad Kawasaki QA/QC on the bolts?

Background is – while cutting grass a couple days ago, mower drive belt busted (bummer). Disengaged PTO, drove ZTR back to the garage (it drove/moved fine, transmission drive belt fine).

Bought and installed a new mover drive belt. Checked the mower belt idler tensioner spring length, all good (11.3/4”). Started engine, went to move mower out of garage to run at no-load condition for a few minutes to break in the new belt – however – had a problem getting the ZTR to move (only moved VERY slowly). Looked at the transmission drive belt with engine running, appeared to have a lot of ‘slop’. Shut engine off, pulled on the transmission drive belt, definite ‘slop’ in its tension – BUT – when I pulled on the belt, also noticed the engine ‘moved’ slightly (not good). Whaaaat?

Grabbed the engine and found I could move it, so looked under the ZTR and found all 4 bolts that secure the engine to the frame missing.

Briefly considered trying to raise engine end of ZTR and then drilling/tapping the 3 sheared bolt stubs to remove them but more effort required for that than I can currently muster (I’m an old guy).

Took my IS700Z to my closest Ferris sales/service/parts store (not where I bought my Ferris). Explained my problem and asked if they could get the Kaw. Engine secured to the frame again (yes they can). Surprisingly (to me), they said “yeah we’ve seen this a couple times before and have had to remove engine / drill and tap bolt stubs out / install new bolts – and in once instance we had to replace the aluminum engine crankcase cover because the 4 x threaded portions of the cover where the bolts secure the engine to the frame had buggered threads”.

 

[txmowman]

The bolts are not provided by or installed by Kawasaki. Ferris builds the mower. The only time I’ve seen this is when either a mower was dropped coming off the back of a truck or the operator was going over curbs, causing a jolt to the mower. You’ll probably want to wait on a reply from Bertsmobile though. He’ll probably tell you a story about the planets aligning as being the cause.

 

[StarTech]

Improperly torqued bolt (screws) or wrong grade used. I have seen several here on commercial JD ZTRs. Even have mufflers to be broken. Remove the engine as you might to retap them after removing the old pieces. Here I go to 1/2 Serrated Flange Grade 8 screws when resizing.

On the current Z925 I go lucky that the screws were only missing which was replace 3/8 Serrated Flange Grade 8 screws torqued to 46 ft-lbs. Althoungh I having to put on a $250 muffler this time as part of it was lost.

 

[bertsmobile1]

pounds to peanuts it has been running with only 3 or 2
Once one falls out / breaks off the other sill follow in a short time

 

[StarTech]

Or as one case here being loose and finally breaking off. I had JD Z925A here where two screws were broken off and one finally stripped out the hole. I ended up having to resize three of the four holes after I had to drill out the two broken ones. They jammed in the holes. Even the engine deck mounting holes had to be welded up and re-drilled. And top of that the muffler manifold pipes were broken off.

The current Z950R in the shop had three missing bolts. Got lucky there as they just fell out. But the customer lost the $250 muffler as part of it was completely missing. And the #1 cylinder has a blown head gasket. Just found that as I was hunting an oil in the exhaust port problem. Dang it computer showed I had the gaskets but I can't find it and am pretty sure I used it last Fall. Re-order those $47 head gaskets.

I fairly sure I used them as I remember receiving one severely damaged and had to get a replacement sent out.

So far I have saved 4 of those $250 mufflers by welding them back together.