• If you like what you see here and your interests are compatible with our 30,000 other users, Welcome. Fill out the registration form with your interests, your real name (seen only by moderators) and your city, state or country. Be certain that you have spelled your email address correctly! Your account is then manually checked and approved.

Re-Commissioning K301 motor on 3.5 Genset

Salt

Registered
Hello Stakers-
I am thinking about getting this old genset going again. It has been sitting for a few years. It had been sucking a little air through the fuel separator bowl. Now I think the carb is probably in need of some love.

The unit is built into a RV body so not much clearance sides and back. It pull fuel from one of the bigger RV tanks, through a small separator, fuel pump then carb.
Plant#3.5CM21, SPEC 87114A3-44B, 120V 60Hz 1800RPM
Engine#K301EP, SPEC 47430B
Controller A-246771

Should I be pulling the plug and adding a little diesel and soaking before cranking?
Can I get by with cleaning the carb versus installing a kit?
Any other tips-trick-online manuals?

Please and Thanks!

Salt's first Kolher 3.5 thread
 
Last edited:

Salt

Registered
I found the manuals for the gasoline motor:

https://kohlerpower.com/en/engines/product/k301

But I am striking out on the 3.5CM21 at 1800 RPM. I keep finding a "RV" type with a K181 at 3600 RPM.

Maybe it is just as well for now as the motor is the patient not the plant.

Motor has sat for a few years. Anything special to do before trying to start it again? Normally I try to run everything a couple times a year to avoid this sitting too long thing but this one was last on the list after it struck out a couple times.

Also looking for advice on carbs, fuel filters, fuel pumps- are the Ebay and Amazon offering worth it? Better to rebuild OEM's? Any issues with modern fuel formulations?

Thanks!
 

Salt

Registered
Fables of the de-construction....
Float needle was stuck in seat. It has the rubber tip but did not look swollen or nicked.
Gaskets: some good, some bad including my homemade fuel bowl one.
I am still trying to figure out what the zip ties are for on the shut-off valve.
Carb bowl was dry, strainer bowl had a teaspoon of honey-like varnish.
Crank oil seemed thin, about 70 F (21 C) outside but did not smell like fuel. This has not been changed ever since I've had it.

So good health, an oil change, some rebuild kits, and gaskets for all?
Remove the automotive filter and stick with the fuel bowl? Or remove both and use a simpler, clear inline filter?

Thanks!

salt_k301_apart0.jpgsalt_k301_apart1.jpgsalt_k301_apart2.jpgsalt_k301_apart3.jpg
 

Mike G

Registered
Last Subscription Date
12/11/2014
When I did a full rebuild on my Wheelhorse's K321 Kohler, I tried to use as many OEM parts as I could. Did it really matter? I don't know. Many aftermarket parts are made by the OEM suppliers anyway.

The carb was pretty easy to rebuild, I think I used an oem kit for that. I even walnut shell blasted the outside to clean it up. If there is slop in the top "bearing" of the throttle shaft, you can usually press a brass bushing into the counter-bore in the aluminum casting. This will help with any air leaks, and make governor response better by eliminating some slop. Someone online was making them, or you could easily make one if you have access to a lathe.

For the fuel pump I chose an aftermarket ("aftermarket from OEM supplier") from amazon. The OEM ones were either very expensive or difficult to find. Its been running for 6 years with no issue.

I run an inline filter in the fuel line, no fuel filter bowl was installed on the tractor I have. Cheap and easy to replace. Clear plastic ones make it easy to see how dirty it is inside.

Regarding fuels, we never had an issue with normal ethanol fuel. After the rebuild I found a local station that sells ethanol free fuel, so i just run that in all my small engines.

These engines are probably some of the best Kohler made, well worth the effort to clean up and get running again.
 

gdstew

Registered
Kohler makes a needle & seat kit for the carb, easy to do. Just remove top needle and clean everything. I liked the B & S fuel filter 691035 which was a paper filter. Kohler does not sell a fuel pump kit anymore ( lawsuit) and their new pumps were very expensive. Usually a good cleaning of the check valves inside the pump is all it needs. Be very careful you do not break a check valve, they are somewhat fragile. Just spray them off. Use a good #30 oil for summer use, something diesel rated for high heat
 

Salt

Registered
Thanks Everyone!
The fuel pump diaphragm looked whole on the inside but the corners outside the mounting bolts seemed a little frayed or de-laminated.
I did not take apart the valves yet. Is it a matter of the one screw and being careful to get all back as before?
I found a roll of gasket material in the RV that I am guessing I bought for this. So I tried a new CAD program (QCAD, fee version) to draw them up.
Normally I would run this out on a laser at work but I cannot easily do that while working at home due to COVID-19 stuff (sheltering in place, still healthy here) so I may just buy them this round with the rebuild kit. The half-moon bowl gasket seems to be a thinner/different material anyways.

Thinking about cleaning everything up in the meantime and painting the air cleaner. Would one paint the aluminum castings as well?
.
salt_k301_phram1.jpgtp_2379_fig6_2.jpgsalt_k301_gasket0.jpgsalt_k301_gasket1.jpgsalt_k301_gasket2.jpg
 

Salt

Registered
Parts are being assembled for the rebuild of the carb and fuel system.
-Locally sourced fitler and hose
-Locally lasered gaskets
-Mail order rebuild kits and gasket set
The lasered gaskets turned out nicer than expected.
My fuel line had both a bowl and filter, bowl seems to be jerry-rigged with zip ties so I may just use the new filter for now.
 

Attachments

armandh

Registered
Last Subscription Date
09/02/2010
just finished my 3rd fuel system overhaul. the corn enhanced fuel just gums everything up over time.
rather than the "tank-under" system I've switched to a dip tube so that the 'cool down and later run dry" can be from a different container.
two 5 gal containers of aviation 100LL should last a long time. I added a squeeze bulb pump to easily prime the system
new fuel sys.JPG
 

Salt

Registered
just finished my 3rd fuel system overhaul. the corn enhanced fuel just gums everything up over time.
rather than the "tank-under" system I've switched to a dip tube so that the 'cool down and later run dry" can be from a different container.
two 5 gal containers of aviation 100LL should last a long time. I added a squeeze bulb pump to easily prime the system
Very nice Armand. Mine plumbs into the fuel system of the 'Mothership' but I may consider something like this.

The 'Mothership' started today after sitting all winter, hooray!
That got me excited to work on the fuel pump.
I broke it down...maybe too far...but one of the discs in the valve body was stuck to its seat so I am glad I did, too bad I did not have a fresh gasket.
I had to file the rod end of the new diaphragm a little to slide nicely into the lower half of the pump.
I got it all together and it makes a satisfying 'slurping' sound when the rocker arm is worked.
Then I found an unknown part on my bench, shown next to a sports ball inflation needle.
Looks like a needle but is too rough to be factory. Could it be from the fuel strainer bowl?
I am done for today. I am going to skip the bowl, add an inline filter, and clean up the carb.
salt_k301_fp0.jpgsalt_k301_fp2.jpgsalt_k301_fp1.jpgsalt_k301_fp3.jpgsalt_k301_mystery.jpg
 

nblack

Registered
I would recommend "Now and Then Automotive" in MA. They have helped me out a number of times with fuel pump parts over the years. They MIGHT even MAKE you a diaphragm for the fuel pump as well. (it's kinda what they do??) I have had very good luck with Tulsa Engine Warehouse (TEW) over the years as well for carb kits for the K series as well (I have a TON of the REAL cub Cadets) (OK, maybe 3) and their parts kits have been just fine. Fuel bowl kits I get from none other than TSC. Exact fit. Cheap.
 

Salt

Registered
I would recommend "Now and Then Automotive" in MA. They have helped me out a number of times with fuel pump parts over the years. They MIGHT even MAKE you a diaphragm for the fuel pump as well. (it's kinda what they do??) I have had very good luck with Tulsa Engine Warehouse (TEW) over the years as well for carb kits for the K series as well (I have a TON of the REAL cub Cadets) (OK, maybe 3) and their parts kits have been just fine. Fuel bowl kits I get from none other than TSC. Exact fit. Cheap.
Then & Now Automotive
447 Washington St, Weymouth, Ma 02188
Monday – Friday: 8am – 5pm (EST)
Ph: 781.335.8860, Fax: 781.335.1925
http://www.then-now-auto.com/

NBlack, Thanks for the tip. I don't think I'll need them for this but might for stuff on the 'Mothership'
The filing on the diaphragm rod was minimal.
'Starting to think my mystery part is flash from a mixed tin of nails and screws I sorted a few days ago.
'Starting to also wonder if I should disassemble pump and figure out a new gasket. It did not look horrible, it might swell up and reseal, but now would be the time. I could maybe use the old thin half-moon gasket from the carb bowl. Thoughts?
salt_k301_fp4.jpg
 

Salt

Registered
A little trouble in paradise...
Started in on the carb.
Needle on side 3 1/4 turns to soft seat
Needle on top 2 1/2 turns to soft seat, pulled it out, found it cracked and bent. So, new main needle and seat?
Also wondering about 'flash' on the casting of the carb, should this be removed?
Thanks!

salt_k301_carb1.jpg
 

gdstew

Registered
The main nozzle ( seat) is non-replaceable, Kohler does not sell them. They install them, then cross drill into them. Getting the holes to line up would be rather difficult. Walbro cut a groove around their nozzles so the fuel could come in the outside hole and slide around to the inside hole. You may have to modify your nozzle likewise.
 

nblack

Registered
OK, The needle Kohler part # should be (if it hasn't been superceded) KH-200410. I would just try the Needle first, as the main Jet may actually be OK. (after a good cleaning, of course!) BTW, a cursory search the t'other night yielded a few positive results regarding the fuel pump gasket. Non-OEM, though. Another source that I use from time to time with very good results is :
https://www.mymowerparts.com/ Kevin Caudill is the owner/part owner? He is very nice to deal with, they answer the phone just about any time of the day or night, and he has helped me to find some really arcane stuff from time to time.
On the flashing, I would gently trim it off level with the casting.
Rotary makes some good parts kits for the Kohler carbs as well, and they are usually reasonably priced.
 

Salt

Registered
Thanks Everyone. The needle seems sourceable at approx 40$ US but if I damaged the carb by removing the needle seat....is it time for an aftermarket replacement carb? Is what you pay for what you get for replacement carbs? Are any replacements better 'bang for buck' than others?
 

nblack

Registered
Yikes! has it been that long since I bought that sucker? That is cwazy!! Lemme do some diggin' I for one, have an EXTREMELY dim view of the china knock-offs. Just sayin'
Found a source for the main needle for just over $20.00 plus shipping? If you need, let me know, and I will compile an order and include your part.
 
Last edited:

Salt

Registered
NB, I appreciate the offer and accept!
My needle is marked 235415-S if that makes a difference.
Let me know how you want to exchange details so the money and part end up at the right places.
I want to say 'personal messages' have been replaced by 'conversations' on the forum.
 

nblack

Registered
Doh! I mistakenly gave you (and researched) the part # for a 7-8HP Kohler high speed needle :headbang:. I will look again tonight for the PROPER part.... No worries. I have (ahem) sources.....
 

Top