exhaust woes

[erick herdt]

I recently swapped out my old tired Onan 24hp for a shiny new Kohler 28hp water cooled. The switching of things went smooth, but I gots me a problem of biblical proportions.

When I ran it the other day, after about 1/2 an hour I went out and checked things over, and noticed my exhaust was glowing bright red.

I changed a few things today, to try and give it better flow through the pipe.

Does anyone have any thoughts of why this would be happening?

Things to consider:

-It's 1" pipe all the way from the engine to the HX.

-The Onan has a higher displacement than the Kohler but never had this problem.

-The Kohler runs at a higher RPM... more output?

-I have welded the exhaust a lot, so that might my issue, with internal restrictions and what-not.


I am to the point of scrapping the whole exhaust and making something new with smoother bends.

Any ideas from the Gurus??

Thanks a MILLION!!

Erick

PS. It's in a early 90's Prochem Bruin (non-catalytic)

 

[Farenheit251]

My Koehler 25hp air cooled is always glowing red. Never considered it a problem. I know from talking to John at Hot heat exchangers that my exhaust is about 1300 degrees while Briggs and others are closer to 1000 so that may be why. (not a bad thing if you use heat exchangers) A broken exhaust and the potential for fire or other damage always concerned me so I had John make me stainless headers. Only like $200.

 

[Shane T]

My 31 hrs Kohler glows red all the time. The original header was made of carbon steel and didn't last a month. It was replaced with a SS one and no problems since. It is best not to have sharp bends but if your sized properly even this won't be a problem. You should wrap the header and other pipes to prevent damage to other components.

 

[Greg Loe]

Just spray some water on it to cool it down. Just kidding!!!

 

[The Magician]

I would get Johns SS header pipes. Less restriction less overheating. Are you running a radiator?

 

[RichardnTn]

Ditto, Jimmy's comment...RR

 

[Larry Cobb]

Erick;

We use a lot of Kohler engines on our TMs and the red glow is common on brand new exhaust pipes.

After a few hundred hours or so, the carbon build-up will slightly insulate the pipe. The operating temp will go down some.

1" pipe is fairly small. We use 1.5" SS tubing for the main tube in our headers:

Do you have any right-angle joints in the header??

Larry Cobb

Shane: The original steel tubing only lasted 1 month ??

 

[Jay D]

Wait till you see it at night. It is red but don't worry about it my 27 was that way at night. Looked like a branding iron out of a fire. If you are running a steel exhaust manifold I wouldnt wrap it. Just leave it. Is your flex pipe between the manifold and the heat exchange SS or what? SS will last alot longer. Kohlers put out more heat than a briggs. Hotter water and components.

 

[R W]

I noticed that my 23 HP Kohler on my Powermatic (when I ran it in the 90's) would glow bright red after dark. My Genesis will glow at night under full vacuum and RPM's.

 

[Dom Agostino]

Had a HM with a water cooled Kawi and those exhaust pipes use to glow after few minutes. In the beginning they had flex pipes which use to burst regularly and finally they went to solid SS, problem solved.

 

[Rex Tyus]

I have a pressure washer that glows red. Touched it once to see if was as hot as it looks.


Yep! :shock:

 

[floorguy]

blockage somewhere giving you restriction...causing the heat build-up


had that problem, till i found the blockage and took it out....which in turn i took out the exchanger..but i have a rippen lp burner so i didnt care...


now no more red for me...and the damn motor pulls a lot better

 

[Shane T]

Larry, I exaggerated. It was 4 months.

 

[KBRENNY]

I have the newer 36 hp Kohler and the entire muffler was glowing bright red at night. I called kohler and they mentioned the fact that it had a fixed jet 2 bbl carb setup that was set rather lean from the factory for EPA reasons. They sent me a new carb at no charge and it helped a little bit but after long jobs ( 4 hours or longer) it still glows a little bit. After talking to a few kohler owners it is not that unusual because most kohlers run alot higher exhaust temps.

 

[Becker]

Nothing new,just the 1st time you noticed it.

I have a exhaust from John's. That thing will last forever! heavy ga SS.

It is wrapped in heat tape, but when not.. It is pretty at night!

 

[glenboy]

red hot exhaust

ran a century with a briggs and its pipes were red all the time so we wrapped them in white asbestos exhaust wrap it kept fire potential down also

 

[erick herdt]

not a little bit of glow

These things are glowing like they are fresh from a blast furnace. even during the day it's scary as hell. At night, it's insane.

I got an area with some 90 degree bends on it (near the Y of the pipes). and I know for a fact there's some serious restrictions with the welding I did on it trying to get it to fit.

I will keep ya updated as this progresses.

 

[JFRASER]

red hot

I have a Steamway 2100 with a 27 horse kohler. Does anyone make a ss exhaust for my set up?

 

[Becker]

http://www.hotheatexchangers.com/

 

[Greenie]

Holy cow, Jeremy finally made it to Mikey's.

How is your 27 running?

 

[Larry Cobb]

Jeremy;

We have Stainless Exhaust Y-Manifolds for the 27 HP Kohlers.

They come straight back from the right exhaust outlet (back of engine).

I don't know the exact layout of your Steamway.

Larry Cobb

 

[JFRASER]

Becker, Thanks for that website I think they can help me.

Larry, I don't think a Y-Manifold will fit I have less than 6in for it to fit. The one on there now looks more like an F.

Greene, the 27hp runs great I don't know why Steamway still uses a 25hp in the 2100. Those 2 extra horses really do seam to help. Thanks alot for the boost to get on this awesome forum, who needs sleep anyway right.

 

[Shane T]

Larry, Are you saying that the tube immediately off the the engine is
1 1/2" or are they smaller and the collector is 1 1/2"?

 

[Duane Oxley]

We use a lot of Kohler engines on our TMs and the red glow is common on brand new exhaust pipes.

After a few hundred hours or so, the carbon build-up will slightly insulate the pipe. The operating temp will go down some.


This gets to something I've been saying about heat exchange systems for some time now... They soot up. And as they do, efficiency drops...

I'm not saying that it's "terrible"... Just that it's a similarity with L.P. systems...

Part of the patent I filed takes this under consideration and describes my solution to it...

 

[Shane T]

So far my experience with the Kohler engine has shown that they run far to hot to even begin to have any carbon build up. There has been no build up in the manifold, diverter, or even the tail pipe for that matter.

 

[Duane Oxley]

It's not a matter of how hot the exhaust is... it's how clean it's burning in the first place...

Air filters not being clean, and even plugs not gapped properly... or changed when needed... cause it to burn rich...

 

[glenboy]

my buddy took me too southern ohio to pik up a used snap
-on tool box truck halfway back i opened the hatch on the engine cover inside the truck and and golllly geeeee those manifolds on that 454 big block were just a glowin i was worried at that point but we drove 300 miles no prob.your pipe is only1.5 " YOU WOULD BE GLOIN TOOOOOO

 

[Outnumbered]

Glowing pipes indicate a lean condition. Just as stated above the carb is jetted lean from the factory to meet EPA emission requirements. I'm not familiar with the exact carb on that particular motor but the carb needs to be jetted a little ritcher in the mid and high circuits which may require a needle position adjustment as well as a main jet with a higher flow. The idle circuit should be left alone. I have some years of experience tweaking motorcycle carbs and these TM motors are very similar. I don't care how good your pipe flows, if your motor is running lean the pipes will glow. I'm new to the CC biz but I think the experience overlaps. Hope this helps.

 

[Greenie]

Great John, welcome to the board, I need a carb guy in the HP room, I get these small engine guys always askin' about carbs ad stuff, I'm not a mechanic.
If you are not a supporting member, I just bought you 6 mo., I need some help, you up to it?

 

[Outnumbered]

Great John, welcome to the board, I need a carb guy in the HP room, I get these small engine guys always askin' about carbs ad stuff, I'm not a mechanic.
If you are not a supporting member, I just bought you 6 mo., I need some help, you up to it?

Very kind of you to offer but I am hardly an expert. Just a tinkerer who has learned a few things jetting my own bikes. I am new to these TM motors and would not feel comfortable giving advice beyond basic concepts, like above.

I'm busy gathering used equipment to start up my own business and maybe after I get a chance to mess around with some of these motors I'll feel a little more confident

I may be calling you soon to get some info on your glides. They seem to be popular around here.

Cheers