Onan inspection port

[kpinnc 13,728]

Thought this might be of use to other 520 owners:

 

My 520-H is a solid worker. With my zero turn needing a new PTO clutch, I've had no choice but to use the 520-H as a backup mower. Everyone knows the dangers of this with the "rear cylinder woes" that can happen with a P220 Onan on a Wheel Horse. Mowing grass of course can result in clippings getting stuck all over the cooling fins, and it's game over. My "modded" Exmark deck doesn't have the clippings issues on the flywheel side, but nonetheless it is always on my mind... And taking the shroud off just to check is a pain.

 

Vanguard "big block" engines have the entire face of the shroud on both cylinders  removable for the same reason. Two captive screws, and you can inspect the cooling fins regularly. That got me thinking...

 

So I had some 1.25 inch nylon plugs in a parts bin. They have tabs on the back and hold very well. I took a spare shroud and "mapped" the safest place to drill the rear of the shroud, and used a hole saw to pop out a 1.25 inch hole. I'm happy to report clean fins, and now I can routinely inspect them so I know the rear cylinder stays cool. I'm gonna have to get a decent borescope, but I can see well enough to calm my nerves for now at least.

 

I'll probably change the nylon plugs for silicone firewall plugs later, but for now I can inspect the fins and spray them out (car wash nozzle) if needed. 

 

[ri702bill 8,968]

Better to modify the original for functional use now than to leave it original and deal with he inherent problem that causes damage....

Did it void a warranty - I think not!! (and too bad if it did!!) 

[kpinnc 13,728]

1 hour ago, ri702bill said:

Better to modify the original for functional use now than to leave it original and deal with he inherent problem that causes damage....

Did it void a warranty - I think not!! (and too bad if it did!!) 

 

Agreed!

 

Yeah, got a feeling the warranty is about 30 years out! I hope it makes it a few more!