Jacobsen Estate 26 with J321 engine with Walbro LMB 150 carburetor pulling too much gas

[Oliver Baer 4]

Hello -

Love the Wheel Horse tractors. Hopefully, it is appropriate to post non Wheel Horse, however related, posts here. My question is in regard to the carburetor on a 1961 Jacobsen Estate 26 with J321 engine and Walbro LMB 150 carb. I recently acquired this from my mother in law who has had it in her family since 1963. It has not run since the 1980s. After careful inspection and cleaning, I chose to remove, dissamble and rebuild the carburetor using a replacement kit.

 

Upon calibration using all defaults (ex. needle idle backed out one full turn from seated) and reinstallation, the engine brielfy fired! However, it ran rough so I tuned the needle idle adjustment to what sounded the best, smoothest and leanest. I am no carburetor expert, so I am just doing a little research and doing best I can. I got it to run and barely idle for about 10 minutes, albeit rough on both the high and low end.

 

After the initail test, I reinstalled the throttle, choke controls and covers. Expecting it to restart easily, it did not. I checked the condition of the plug, and it was soaked in gasoline. I cleared the cyclinder pulling the starter cord with the plug out, while double checking the spark, which looks good.

 

It appears that the cylinder is pulling too much fuel through the carburetor. The idle jet is pretty straightforward, so I shifted my focus to the  needle assembly power. There does not appear to be any adjustment for the power setting.

 

Does this make sense to everyone?

 

I removed the carburetor and double checked that the needle assembly power does not have any adjustment and it does not. At least, it does not appear to. The parts illustration (attached) shows three variants of the needle assembly power. The one on this particular J321 looks like the one highlighted in the illustration.

 

Does it make sense that the power inlet to the venturi would have no flow control and it could just suck as much gas as can flow through the tube?

 

Any suggestions that anyone could offer would be greatly appreciated.

 

Is there an alternate or recommended carburetor that could be used? I am a traditionalist. Thinking it worked before, it would be nice to get it runnning in original stock condition.

 

Thank you,

Oliver Baer

[Snoopy11 5,718]

I saw this thread in my email just now... I instantly thought that the float is sticking in the carb...

 

Don

[Oliver Baer 4]

Don,

Thank you for the quick response. I will check the gas inlet to the carb and see it the float and needle valve appear to be working. I was very careful when rebuilding the carb to ensure that the float and needle were/are functioning. Will check and report back.

Thank you,

Oliver  

[ri702bill 9,358]

Welcome!! Did you check to see if the float has gas inside it - it shound not make a sloshing sound if you hold it up to your ear and shake it. If it is fuel logged, it will sink rather than float, and never shut the fuel off. If so, it can be repaired.....

 

[Oliver Baer 4]

Thank you, ri702bill. Great idea and insight. Yes, I did check the float to see if I could hear any gas inside. Visibly and audibly it seems in tact.The needle valve closes when the carb is turned upside down.

 

With these "fixed jet" carburetors, is the regulation of the amount of gas at throttle controlled by the amount of gas in the bowl? Seems like some way to regulate that would be beneficial.

 

Are there alternate period appropriate carburetors like Kohler that are suited for the J321s?

 

Thank you,

Oliver

[ri702bill 9,358]

The Carter Model N carb MAY be a good alternative - has adjustable idle and high speed jets.

You want one from a 10-14 HP Kohler - there is a two digit number cast into the body, visable with the choke plate wide open. Not sure of the one you need - number reflects bore size and CFM. Look for one that matches your current carb bore.

You do not want a 20 or 22 - those are 7 and 8 HP carbs with a smaller mounting flange...

[Oliver Baer 4]

Thank you everyone for the comments and insight. Very helpful. I rechecked the float and needle valve. When the valve is supposed to closed (float up), there is a slight amount of passage permitted (via air test). The carb was just rebuilt and I used the new replacement needle valve. Just for kicks, I tried the old needle valve and the seal was much better. (Note: I carefully reinstalled the new needle valve seat with retaining ring and double checked that that is all correct). After reinstalling the carburetor the engine fired right up. It is running rough and I cannot get it to throttle up to high speed. It does idle reasonably well. Again, it has not run since the early 1980s, so it is great that it even runs. If I can figure out the high speed running issue this Jacobsen will be on the restoration list this winter.

Any insight or guidance would be greatly appreciated. Again, thank you to all those that helped along the way with their comments and suggestions.

[TonyToro Jr. 1,933]

to !!!!

[Jeff-C175 7,206]

4 hours ago, Oliver Baer said:

insight or guidance

 

Explain how you 'cleaned' the carburetor.  Did you soak it in Berryman's ?  Spray it with carb cleaner ? etc ?

 

There's small passages that could be blocked by 'crud'.  Try to get the 'straw' from the carb cleaner into those small passages.  PROTECT YOUR EYES!!!!!!!!!!

 

Did you adjust the float level appropriately?  This is typically done by bending the little tang that pushes the float valve needle.  Should be a spec somewhere for the adjustment.  Usually, if you invert the carb, the float should be parallel to the carb body, or just slightly 'up'.  

[Oliver Baer 4]

9 hours ago, Jeff-C175 said:

 

Explain how you 'cleaned' the carburetor.  Did you soak it in Berryman's ?  Spray it with carb cleaner ? etc ?

 

There's small passages that could be blocked by 'crud'.  Try to get the 'straw' from the carb cleaner into those small passages.  PROTECT YOUR EYES!!!!!!!!!!

 

Did you adjust the float level appropriately?  This is typically done by bending the little tang that pushes the float valve needle.  Should be a spec somewhere for the adjustment.  Usually, if you invert the carb, the float should be parallel to the carb body, or just slightly 'up'.  

 

Thank you, Jeff. With regard to cleaning the carburetor, I disassembled every physical part on the carburetor, sprayed all the orifices with carb cleaner (Yes, even the very small ones), double checked passage clearance with air, then sprayed and let sit, then one more time, then carefully reassembled. The most difficult part was making sure that the needle valve seat was in the correct orientation and the clip engaged in the recess.

 

I did not have to adjust the float calibration. I did check to make sure that when the carb is inverted that: 1) the float is just above horizontal when the needle seats, 2) that the needle does in fact seat and seal with light air pressure, and 3) that the float has enough clearance to move up and down to pemit the needle to engage and disengage.

 

I did hear from someone that carbon buildup in the cylinder might have losened up from amount of gas oil mixture that was ingested by the engine and this might be clogging the valves. It was advised to remove the exhaust, inspect and clean. It seems probable since the first time it fired it did in fact rev higher and how it does not after dousing the engine with gas-oil from the float not seating.

 

Does that seem probable? 

[Jeff-C175 7,206]

11 hours ago, Oliver Baer said:

regard to cleaning the carburetor

 

Sounds like you did a good job Oliver.  

 

11 hours ago, Oliver Baer said:

carbon buildup in the cylinder might have losened up from amount of gas oil mixture that was ingested by the engine and this might be clogging the valves. It was advised to remove the exhaust, inspect and clean. It seems probable since the first time it fired it did in fact rev higher and how it does not after dousing the engine with gas-oil from the float not seating.

 

Does that seem probable? 

 

I like to say; Anything is possible!  Just the other day I had a brand new float needle get stuck and wasn't getting fuel.  Unlikely, but it happened!

 

But, I'll add that the carbon won't be enough to 'clog' the valves.  Sometimes a piece of 'junk' will get stuck under a valve seat temporarily and prevent the valve from closing fully.  If there's an EXTREME amount of carbon buildup, odd things can happen.

 

Sometimes the exhaust can get plugged up but I don't think that's highly likely.  Happens more on 2 cycle engines.  

 

On that line of thinking... what about MICE?  I recently resurrected a car that was in my back garage for a couple decades and when it finally started, I could not believe the amount of crap that the mice had packed into the exhaust system.  What a mess when that 5h1t came flying out all over the garage... probably Hanta Virus Heaven!  So, check for that, and also underneath the engine tins.  They love to nest there.

 

Keep in mind that a spark plug doused with gasoline won't fire well, if at all.  So perhaps that's what happened?  Plug got gas fouled?  Usually you can pull the plug, blow it clean with some carb cleaner, let it dry and re-install.  

 

Have you made any progress since yesterday?

 

 

Edited October 29, 2022 by Jeff-C175

[Heatingman 971]

The valve could be stuck/sticking or otherwise blocked from sitting so long particularly if it was outdoors or stored in a humid area.

 

Had a motor that sat a good long time that I bought for a pulley I needed that had a stuck exhaust valve from rust.

 

 

[Oliver Baer 4]

Thank you everyone for the insight on my problematic Jacobsen Estate 26 with J321 engine and Walbro LMB 150 carburetor. Spring is here and it is time to regroup on getting the Jacobsen fully operational. Just like last Fall, the engine ran only at idle and did not review despite increasing the throttle and manually increasing the throttle regulator. The carb was double checked by removing it [again] to make sure that all passageways are clear, which appears to be the case. I also re-inspected the exhaust manifold and cleaned the carbon buildup, which was minimal. The engine started on the second pull, but continues to only run at idle.

 

With there being no high speed adjustment on this Walbro LMB 150 carburetor, what could be restricting higher RPMs?

 

Any additional thoughts would be greatly appreciated.

 

Thank you.

[ineedanother 1,668]

I feel your pain man but this might not be the place to solve your problems with a 2 stroke (sorry to say that ) but they are not common here. I would definitely look to eliminate the muffler first and then the carb as the nagging issue before  If it were in my shop, I would remove the muffler entirely and start it briefly to see if the same issues were present and symptoms persisted. If they do, break that carb down to include welch plugs and get it in an ultrasonic cleaner with a solid rebuild. Ideally, find a substitute carb to install which would tell a lot.

 

https://www.dicarbparts.com/custom-carburetor-kits/403-jacobsen-j321-j501-carburetor-walbro-lmb151-lmb166-lmb167-lmb172-lmb173-lmb195-carb-kit-di-26101.html

 

 

[oliver2-44 10,691]

Put some mixed fuel in a squirt bottle. With the engine idling spray some into the carb. The engine should speed up. If it doesn’t I would pull the exhaust as others have suggested. With exhaust off spray some fuel in again and see if it speeds up 

[Oliver Baer 4]

Thank you for the additional suggestion to check the exhaust. I did remove it last year and it ran intermittently faster than idling. Will try that again - and spraying gas mixture into the carb inlet while idling - and report back in a day or so.