Hello Jeff
The Muffler is bolted behind your PTO. To remove it, you will have to Take the electric PTO off of your Onan. Remove the PTO to get at the Muffler Bracket's bolts. Once they are removed you can remove the Muffler assembly from your engine. Some Guy's slot the Muffler bolt hole's so that the Muffler can be removed without Taking the Electric PTO clutch off. Mine are Not slotted I decided to leave them they way that they were made and I have to Take my PTO clutch off to remove the Muffler. You can Loosen the Two Muffler clamp's and Try to separate the Muffler stub pipes that run to the Exhaust Port of your engine. Typically the Muffler rust's some right at the area where those clamp's go as well as it is some what Crimped down from the Tightening of these Muffler clamp's so it can be hard to separate the short stub pipes. I would suggest that you simply Pull The PTO Rather than take a chance breaking something trying to force the Two short stub pipe's apart. I hope this helps, Kurt

 

Thanks Kurt, I have not looked at it real close yet, but does the PTO need a puller, or is it just bolted around the outside?
Need to get out there and clean all the top of the engine first, but from looking at it at a glance, I thought the PTO might have to come off or be able to spin it around a bit after taking the bolts out to get to the muffler bolts. Jeff

 

Shouldn't need a puller Jeff just tap on it lightly with a brass hammer and it should slide off. Dave

 

Jeff your observation of just turning the PTO to access the fasteners worked for me in the same circumstance. Mick

 

The bracket that holds the muffler and goes down behind the PTO clutch has been cut on my 316. Looks like a very small thin cut with a torch. Don't have to take anything off, just loosen the muffler clamps and take the muffler out of the way, then you can take the two pipes from the exhaust on the cylinder heads.
DAve IN SW Missouri

 

Thanks for all the help and suggestions. I hope to get all the gaskets needed in soon, and can get to the job. I looked at it today, and as Mick said, I think I can loosen the PTO bolts up and just turn it around to where there is a flat spot, looks like I should be able to get to the 2 bolts that hold the muffler bracket to the front of the block.

 

Hello Jeff
If you need to take the PTO bolt's all of the way out of the engine block Pay close attention to where they came out of as in my engine they differ in length and may bottom out without Tightening the PTO back correctly. I use my air Impact gun to remove the center bolt and a 3/8" ratchet and extension with a deep well socket to remove the four PTO Bolt's if you decide to go that way. I remove mine in Fear of damaging the PTO itself they are pricey and we are Talking just Five bolt's to remove counting the center bolt. When going back on with the PTO should you remove it, make cure your Key stock is pushed toward's the rear of the notch in the crankshaft, & That you line it up with the cut out on the back side of your PTO when you Push it back into Position on the Crankshaft. In removing the PTO I always' have to adjust the air gap once it is back in position, the same as you will have to do by Loosening the Three Nut's that hold it in place. I go a Little Tighter than Spec. on the air Gap I run mine at 0.015" and it seem's to engage and disengage much quieter. I hope this helps, Kurt

 

jeff
when you reinstall the bottom two bolts for the
clutch adapter, you want to put thread
sealer on them.
that is because they go into the crankcase,
and may leak oil without the sealer.
thank you boomer

 

I plan to adjust my 318's valve clearance in the spring when it warms up a bit so have been following this with interest. I plan to remove the exhaust pipe/muffler as one unit just to avoid the rust/reconnection hassle with the muffler clamps.

Many recommend taking the PTO off to check the pulley/armature slides freely on the shaft as good PM practice.

Not to disagree with Boomer (as he is always correct), but if I recall correctly, the adapter plate that the PTO field coil mounts to doesn't have to come off so there are no bolts that go into the crankcase needing thread sealant (assuming you don't remove adapter plate)

If you want to take the adapter plate off to go deeper, then Boomer is correct, need thread sealant on those bolts.