NAA Jubilee dies with load

We have a 1953 NAA Jubilee that we use to mow our runway. Recently, whenever you engage the power take off and run the mower deck the engine boggs down and wants to die. If you disengage the power take off the tractor will run fine at low throttle settings. It seems like a fuel problem. We have cleaned the fuel bowl, screen and blown out the fuel line. Also, the carb has been rebuilt this past spring and we checked the points. It had been running fine.

Was wondering if this sounds familiar to any of you? What common problems we should be looking at. We have an owners manual and have gone through the trouble shooting section to no avail.

Thanks
Don

check the linkage to your governor. sounds like its not working right.

Start with the simple stuff first: fuel and spark.

6 volt or 12 volt?


Check for spark and fuel. (see tip # 13)

You need to answer 2 questions before you do anything else:

With the bolt in the carb bowl removed and the gas on, will the fuel flow fill a pint jar in less than 2 minutes?

Next, get out your adjustable gap spark checker * , open the gap to 1/4", hook it up, turn the key on and crank the engine. Does the spark jump 1/4"? Post back with the answers.

And do not buy a new part for the tractor until you can answer this question: how do I know the part on the tractor is defective?

Once you narrow the problem to spark or fuel, post back and tell us what you found (and how you found it) and you will get plenty of help to get your tractor running.



* Don't own an adjustable gap spark checker? Buy one! Not a test light! Until then, take an old plug, open the gap 1/4" ground it to the head & look for spark. It?s not the color of the spark that counts; it?s the distance it jumps.



https://www.amazon.com/AMPRO-T71240-Energy-Ignition-Tester/dp/B00A8FO87S/ref=sr_1_fkmr1_4?ie=UTF8&qid=1513273147&sr=8-4-fkmr1&keywords=ampro+spark+checker
75 Tips

Sounds to me that your mower may be placing an extra load on your tractor. I'd check the mower to be sure blades, gear box and drive shaft are not causing the problem.

I would pull the spark plugs and check for fouling, you may be running on 3 cylinders.

The little round knob on the top front of the carburetor! Turn it a half around out! Did it help??

Thank you for all the information. I will check everything that is mentioned and get back in a week or so.

We checked the mower deck to make sure that wasn't the problem. Greased the spindles on the deck, checked that the blades turned freely. Cleaned and gap'd the spark plugs, checked and cleaned the points. Followed the directions to run the engine at high rpm and adjust the fuel setting screw on the top of the carb so the engine runs smooth.

Still had the same problem of the engine bogging down under load. Normally we have the fuel valve opened 2 turns. For a test, we opened the fuel valve all the way and the tractor ran fine under load. Sooooo, it seems we have a fuel problem. I'm guessing there is either another adjustment on the carb to allow more fuel in or we need to re-build the carb.

Thoughts?

You may have a bad sediment bowl or a partially plugged one.

(quoted from post at 05:26:19 06/21/19) We checked the mower deck to make sure that wasn't the problem. Greased the spindles on the deck, checked that the blades turned freely. Cleaned and gap'd the spark plugs, checked and cleaned the points. Followed the directions to run the engine at high rpm and adjust the fuel setting screw on the top of the carb so the engine runs smooth.

Still had the same problem of the engine bogging down under load. Normally we have the fuel valve opened 2 turns. For a test, we opened the fuel valve all the way and the tractor ran fine under load. Sooooo, it seems we have a fuel problem. I'm guessing there is either another adjustment on the carb to allow more fuel in or we need to re-build the carb.

Thoughts?

Click to expand...

Don, before removing the carburetor you really should answer the questions already asked of you.

(quoted from post at 13:20:46 06/21/19)

(quoted from post at 05:26:19 06/21/19) We checked the mower deck to make sure that wasn't the problem. Greased the spindles on the deck, checked that the blades turned freely. Cleaned and gap'd the spark plugs, checked and cleaned the points. Followed the directions to run the engine at high rpm and adjust the fuel setting screw on the top of the carb so the engine runs smooth.

Still had the same problem of the engine bogging down under load. Normally we have the fuel valve opened 2 turns. For a test, we opened the fuel valve all the way and the tractor ran fine under load. Sooooo, it seems we have a fuel problem. I'm guessing there is either another adjustment on the carb to allow more fuel in or we need to re-build the carb.

Thoughts?

Click to expand...

Don, before removing the carburetor you really should answer the questions already asked of you.

Click to expand...

b:591a163293][i:591a163293]

Don;
Showcrop has a VERY good point!!!
That aside, Leave the carb alone for the time being....take the sed bowl off/out of the tank and clean out the main standpipe in the sediment bowl.
You said the N runs good with the sed. bowl all the way on....SOOoooo, that means the main pipe of the sediment bowl is plugged, and the tractor is running good on the reserve of the sed. bowl!!!!!
R Geiger already gave you a hint of your problem!!!
Answer all ? ask of you and read ALL the posts to you!!!!

Gary[/i:591a163293][/b:591a163293]

We didn't have a chance to check the fuel flow at the carb drain however, I did take the sediment bowl off and clean the screen. We did find that the tractor runs fine under load if we open the fuel valve 5 turns. The manual says 2 turns for the main fuel supply to flow. Like you say, it sounds like the main fuel line is clogged. How do we access and clean the main fuel line?

Thanks for your help

The best way would be to replace the sediment bowl assy. But i would remove it and try blowing out the passage with compressed air.

(quoted from post at 09:37:37 06/23/19) The best way would be to replace the sediment bowl assy. But i would remove it and try blowing out the passage with compressed air.

Click to expand...

b:e4ade010b8][i:e4ade010b8]

YES, just what R G. Said to do......BUT, just to be clear...you have to drain all the fuel out of the tank FIRST!!!! Then remove the sed. bowl from the tank!!!
If you are able to clear the sed. bowl of the clog DO NOT let that get into the main fuel line from the sed bowl to the carb.
Other wise you will be chasing yer tail around inside the small passages of that carb....and unless you know what you are doing with the carb.......I would not want you to do that!!!!!

Check the tank real good for rust and dirt before you put clean fuel in it!!!!

Gary :roll: [/i:e4ade010b8][/b:e4ade010b8]

Don, you my be opening the wrong valve for fuel flow. Generally the shutoff at the tank is opened and left ALL the way open. While your main JET on the bottom of your carburetor is opened 2 to 2.5 turns for high speed fuel mixture. Flow is also dependent on the passages, screens and lines being clear. You didn't say what you found when you cleaned the sediment bowl. If you are getting a lot of debris, this means that you have a lot in your tank. I have had good success cleaning the bottom of tanks with a siphon.

Showcrop, I'm talking about the fuel valve on the sediment bowl. I found a link (below) showing pictures of the N Series sediment bowl. I think our problem is that there is a clog/sediment in the tube of the main tank pickup of the valve, hence if I open the valve 5 turns it opens the "reserve" fuel pickup and the tractor runs fine without bogging down.

Ford N Sediment Bowl

(quoted from post at 05:23:29 06/24/19) Showcrop, I'm talking about the fuel valve on the sediment bowl. I found a link (below) showing pictures of the N Series sediment bowl. I think our problem is that there is a clog/sediment in the tube of the main tank pickup of the valve, hence if I open the valve 5 turns it opens the "reserve" fuel pickup and the tractor runs fine without bogging down.

Ford N Sediment Bowl

Click to expand...

OK Don, I don't have Ns. I had forgotten about the reserve position valve. I still recommend siphoning to clean the tank bottom and then the sediment bowl. A plugged fuel line is extremely rare. The only time that I have seen it was at a Tee. I suggest AGAIN that you go to Bruce VAs post.