K341 too much fuel pressure.

[bobodu]

Got a really good deal on a Homelite/Jacobson UT 3400. Guy said it floods when running. He replaced the pump and the carb with new. I bypassed the pump and filled the tank and she runs great. I may try to shim the pump away from the block but I thought I'd ask for advice first. I do not suspect a float problem since the new carb is doing the same thing.

[bgsengine]

I'd check fuel pressure from the pump - if it is an OEM pump, simply no way it could create too much pressure (it'd be controlled by a couple springs in the pump) shimming the mechanical lever type fuel pumps away from the cam would be a good way to end up with a busted cam. The pump *pumps* pressure on its return stroke.. the cam moving the lever only creates the suction stroke of the pump. So if you are getting too much pressure, then I'd have to say the pump arm return spring and/or diaphragm spring were too strong.. I would not expect to see much more than 8 PSI from the pump, and any case the carburetor float and needle/seat should be able to hold 10 to 12 PSI (most will hold 8 PSI on their own weight on a bench test, using a pressure/vacuum tester like mity-vac) And finally, might want try and find out the specs on those "new" pump and carb.. I'd have to assume its a walbro carburetor (The original Carters are damn hard to find and very expensive any more, but they were the best!)

[bobodu]

Thanks for that...I have ordered a low pressure electric pump which tops out at 4 psi, but I won't be here for a while....
Since there isn't really a need for the tractor, I'll run it off full tank gravity until then...

[KE4AVB]

Well I going put my penny's worth here.

For Spec number and serial for the K341 are important.

Second their is four versions of the K341 listed for the Jacobson listed and two for the Homelite on Kohler Plus one is gravity fed and the other is pump fed. Knowing about every DIYer will use the cheapest carburetor they can buy it is highly it is a clone. From you description is highly likely they also got a gravity fed carburetor instead of the pump version.

Also two of the Jacobson engine's carburetors are NLA. Also leading to the chance they put on the wrong carburetor. But at least there is both a gravity pump fed that may work.

I suggest replacing the carburetor with a known pump fed version.

[bobodu]

Played around a little. Had a vacuum pump on the shelf and ran it off the breather tube. Would this cause me any problem later?
Opened up the original carb and the float valve is frozen so I'm stuck with the Wuhan carb for a while.

[bgsengine]

Played around a little. Had a vacuum pump on the shelf and ran it off the breather tube. Would this cause me any problem later?

Yes, crankcase still needs to breathe or you'll end up with oil leaks or seals popping out. I've converted mechanical kohler pumps before by getting a fuel pump block off plate (from a Gravity feed engine) and drill/tap for a barbed fuel hose fitting right over the fuel pump opening and used that for the pulse hose to a pancake diaphragm pump.

Opened up the original carb and the float valve is frozen so I'm stuck with the Wuhan carb for a while.

If your original carb is the carter, basic repair kits (with bowl gasket set and new needle/seat) are still available (I think 25-757-01-S if I recall right) floats can be had too (can't think of the part number offhand, rarely replaced those)

[bobodu]

Then that is my plan...
Thanks guys.

[bobodu]

Would it be okay to tap the block off plate?
EDIT....!!! Maybe that what you meant by "right over the opening!!! I was thinking you meant above the opening, into the block...!!!

[bgsengine]

Would it be okay to tap the block off plate?
EDIT....!!! Maybe that what you meant by "right over the opening!!! I was thinking you meant above the opening, into the block...!!!

Yep - just drill and tap the plate. (its meaty enough, and you can always use some loctite, and since it is pipe thread, they tend to self-tighten on that taper) I put it at about dead center of the plate, that way , no block modifications needed.

[bobodu]

Almost always the basics....like never trust what someone else did. I opened up the old carb and found the needle stuck !! Sure... they can be free on the bench ....until a float pushed them up !!! Very distinct groove in the rubber. A new original carb kit ( $23) and ten minutes ( would have been five but I had to turn down a Chinese socket to remove the seat) and all is well with the mechanical pump!!! I ordered a drill and tap from Amazon....I can still use them to add drains to my pontoons...I had a guy weld bolsters to the logs and never got around to tapping them..