MEP 831A Exhaust Size

[sassriverrat]

Anyone know off the top of their head what size the MEP-831A's exhaust size is? I'm not at home right not but looking at a possible exhaust cap I could put on a pipe for it...and I'd like to get the exhaust up and above head level.

 

[kloppk]

I happen to have my 831 apart and got the measurements for you.

The pipe is 1.250" OD and 1.140" ID. The pipe is cut at an angle.

This is what it looks like once you get the cover off and the rubber hose nipple off of the exhaust pipe from the muffler.

 

[sassriverrat]

Hmmm. I was thinking about welding a union on it and then threading either 1.5” or 1.25” pipe the 4 1/2’ to get it above the roofline of my camper build. Any recommendations? I wonder if the 1.5” pipe would help cut down on noise. I haven’t actually seen/run mine yet but I’m compiling parts to put together when I get home. Thanks!

 

[kloppk]

You'll have to take engine/muffler vibration into consideration. Connecting hard pipe directly to the outlet may lead to the muffler cracking.
If it were me I'd look into using some 1 1/4 ID flexible exhaust pipe to do the extension.
That or use a short flexible exhaust hose between the muffler outlet and a hard pipe extension.

 

[sassriverrat]

Good call! Thank you

 

[Guyfang]

Hmmm. I was thinking about welding a union on it and then threading either 1.5” or 1.25” pipe the 4 1/2’ to get it above the roofline of my camper build. Any recommendations? I wonder if the 1.5” pipe would help cut down on noise. I haven’t actually seen/run mine yet but I’m compiling parts to put together when I get home. Thanks!

Keep in mind, if you ever have to take this thing completely apart, welding something to the pipe, may make it harder to take apart. I think Kurt has it right.

 

[sassriverrat]

True. I think I'll plan to set this up with a pipe welded to brackets external to the generator, a 1 1/2" pipe, and a 1 1/4" reducer for hookup via rubber exhaust hose to the generator itself.

 

[kloppk]

For those interested... I found that the Walker 40001 is a perfect fit for the the MEP-831A exhaust.
Bought a 25' length of it and made a flexible exhaust extension so I can run my 831 inside the "warm" garage and vent the
exhaust out one of the garage windows while I'm developing and testing products in the 831.
The flex pipe goes thru a wooden panel in the window.

The Walker 40001 just slips over the 831's muffle nipple. Simply slit the side of the flex pipe about 3/4",
slip a hose clamp over the slit section of the flex pipe, slip the flex pipe on the muffler nipple and tighten the clamp at the slit.
Works great!
The new flex smokes a bit until the manufacturing oil burns off of it.

I also bought fittings so I can use the same flex pipe to run my 802 inside for similar reasons. Bought a Female to Female pipe fitting to step down the 802 exhaust pipe nipple to 1". A short 1" pipe nipple snugly screws into the Walker flex pipe.
Yes... the Walker pipe is slighlty smaller than the 802's exhause size but will suffice for my short term run needs.