Repairs Ferris Evolution with an Engine Speed Issue

I have a Ferris Evolution with a 48" deck powered by a Kawasaki 27 hp engine. I have owned this machine for three years and have overcome shredding deck belt issues during the first year and now have a problem that has me scratching my head. They tell you to run the engine at full throttle when mowing and that used to work great until recently. The engine starts, powers up and mows great but as I mow, the throttle speed continues to decline, literally. If I move the throttle lever back to full throttle, engine speed goes up as normal but it continues to decline as I mow. I have checked the throttle cable and it is tight to the engine so my movement is not due to a loose cable and the cable spring, at the engine, appears to be installed the only way it could be (no additional adjustment holes to either increase or decrease tension).

Has anyone ever run across a problem like this? I am beginning to wonder if the throttle at the control station has a spring or resistance setting that has become loose or worn. This machine has right around 200 hours and short of a bungie cord I do want to make a repair but a proper one.

Any suggestions?

Throttle pulls against a spring and hold there by friction .
Usually it is rivited so pull it out and give it a few remedial "taps".
A dull centre punch or nail punch seem to have the best remedial action.
If you are lucky and have a nut & bolt then tighten .
A star washer will work best to stop it undoing.

bertsmobile1 said:

Throttle pulls against a spring and hold there by friction .
Usually it is rivited so pull it out and give it a few remedial "taps".
A dull centre punch or nail punch seem to have the best remedial action.
If you are lucky and have a nut & bolt then tighten .
A star washer will work best to stop it undoing.

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I looked at the throttle plate on the engine as well as the throttle adjustment on the Ferris. Both held together with rivited connections. The "peened" end is rather small while the other end is a much larger flat disk, about the size of a nickle. I am tempted to remove both, again, grind the peened end flush and replace with a small diameter bolt with flat washer and nylon lock-nut. With that repair, I can better control the tension. A little more work but should be more permanent and I think I can live with the inconvenience for another month or so.

Your thought on my proposed remedy?

That is the most permanent way to fix. Has worked for many on this site. But like Bert said star washer is best. I would use both nylon nut and star.
Do not try yo remove rivet the hard way. Use a drill and drill it out. Hammer and chisel or cutting it off is the hard way. If you have a grinder and are really careful you can possibly grind it off on side then drive it out.

BlazNT said:

That is the most permanent way to fix. Has worked for many on this site. But like Bert said star washer is best. I would use both nylon nut and star.
Do not try yo remove rivet the hard way. Use a drill and drill it out. Hammer and chisel or cutting it off is the hard way. If you have a grinder and are really careful you can possibly grind it off on side then drive it out.

Click to expand...

I figure the trusty Dremel would be the best and fastest way of getting the peened end off the rivet and out of the way. Plus no potential damage to any of the component plates within the mechanism.

Thanks for the review.

mountaincut said:

I figure the trusty Dremel would be the best and fastest way of getting the peened end off the rivet and out of the way. Plus no potential damage to any of the component plates within the mechanism.

Thanks for the review.

Click to expand...

Thanks for the suggestions but some time ago I ripped the control panel apart and found the actual problem. The connection at the main control throttle was not securely fastened. I put it in a vice and peened the connection making it secure. Problem solved!