Ford 800, Which Carb??

[seth350]

Just recently acquired a Ford 800 and in the process of making it perfect-o...or so to say :dance1:

Been having issues with a lean miss at off idle-to high idle, and just a general loss of power after it warms up. I have two carbs here that I have tried out and neither one seems any better than the other, but I have been swapping one rebuild kit into both.

One carb is a TSX-765 (currently on the tractor) and the other is a TSX-593 (EAF-9510-E).

The only difference I can visually see is that in the throttle bore, there is an extra orifice on the 765 off to the side of the other main two. I believe they are the idle orifice and main orifice. The other, I think, is an economizer orifice from what I have seen on the net. However, there is not an economizer adjustment on the bottom of the bowl.

Anyone got an idea of which one would be best?
From what I am seeing the TSX-765 was for the 801 series.

 

[Soundguy]

I know the 593 will fith 800/900

 

[seth350]

Cool thanks soundguy, I wonder if there is any draw back to using the 765 with that extra orifice?

 

[Kirk-NJ]

Shouldn't be a problem as long as the top bolts in the carb fit the manifold. You will probably burn a bit more gas.

Kirk

 

[seth350]

Everything fits perfectly, but it has the lean miss after warm up. Still need to check coil and spark once engine is warm. Just trying to rule out having the wrong carb. I have had the 765 on the tractor and running, but develops a lean miss after warm up.

Really hoping the 765 will work as it is the best condition of the two.

 

[Soundguy]

It should.

Have you tried enriching it just a bit?

Or in other words.. does a hair of choke seem to help it?

 

[seth350]

Thanks soundguy, yes I have enriched it screwed the idle mix screw out and in with no change. Choke does not help either.

 

[Soundguy]

if choke does not help, it is not a lean issue more than likely.

Have you checked valves... you don't want them too tight...

how is timing too? advance working?

 

[seth350]

Thanks soundguy, the valves were set to 15 cold. Timing is set to 5degrees, but only advances up to ~20. I rebuilt distributor as it was sloppy and the advance has some wear on the guide pins and slots. I cleaned and sanded them up to take the rough spots out and it seemingly worked fine. Greased it lightly with some non tacky grease I had.

 

[Soundguy]

recheck valve clearance hot.

 

[seth350]

Will do.

Just found this pdf and found the 593 is for an 800 and the 765 is for a 600. So I have been running on a carb for a smaller engine.
http://www.tomco-inc.com/Catalog/agricutural&indust.pdf

A lot of other information there as well.

 

[Soundguy]

Will do.

Just found this pdf and found the 593 is for an 800 and the 765 is for a 600. So I have been running on a carb for a smaller engine.
http://www.tomco-inc.com/Catalog/agricutural&indust.pdf

A lot of other information there as well.

Yup.. I knew 593 was for the larger engine models.

By the way.. you CAN make the 765 work, you just have to enrich it a bit.

I'm running a farmerized NAA carb on my 950 i mow with.. because it was available and cheap. tsx 428 i think...

 

[seth350]

Cool deal, wonder if I would need to drill out any of the jets a tad? I had just felt that I didnt have enough adjustment. I will check again to be sure. I had read extensively about the lean miss condition some of these carburetors have, and some had drilled out the jet(s) to correct it. Although, my problem is probably not that complicated.

 

[Soundguy]

I have before..

 

[seth350]

Looking back through both carbs, I found the original main mixture adjustment and idle mix adjustment screws to be larger on the 593 vs the 765. All other jets are the same size, except the 765 is missing the economizer jet. So that circuit shouldnt be functioning while the tractor is running because there is no orifice to create a pressure drop. The 593 does not have this circuit at all.

What I planned to do was to swap the adjustment screws from the 593 and put in the 765 to see how much difference they make.

The adjustment needles are ~.020" bigger than the 765.

 

[seth350]

Just an update on my findings for future searchers...

I have finally moved away from tinkering with the carb. I have been adjusting and adjusting and adjusting trying to eliminate the lean-miss sounding sporadic put-put sound. From what I have found, these carbs are extremely forgiving. The 765 is still on my tractor and it is running.
My issues were not fuel related in the first place.

For giggles, I checked to see if the exhaust was actually blowing out the of tail pipe, or if it was sucking in whenever it would make the pffft sound.
It was actually sucking in, so the issue was not fuel related. I didn't want to get into a valve job just yet so I decided to try some snake oil remedies first, because this tractor does not get used unless I go on a romp or snow removal. I tried some water first. Brought the engine up to temp and set RPMs to ~1800. Removed the plug above the carb on the manifold and started adding a little bit of water at a time. I ran about 8oz of water through her and on my last little bit of water, I let it get sucked in and then shut down the engine. Replaced the plug in the manifold and let the tractor sit and steam for about 3mins. Cranked it back up, and no change...still sucking in through the tail pipe.
Went back to my shelf of tricks and got some ATF, did the same procedure. After cranking it back up, it wasn't sucking anymore but was very occasional. Did the same process again with ATF and now its sounding smooth. I knew the intake valves were horridly carbonized, but figured they were seating as I was getting fairly good compression readings, and the wet test proved that the piston rings were worn.

 

[Soundguy]

stuck valves on these, while not wildly common.. are VERY possible.

I have had a couple with stuck open intakes. One stuck so bad it bent all my Intake pushrods.

put some atf in the oil and a heavy dose inthe gas and run her.

sure. some smoke.. but ok top end lube.

If it keeps happening, change the oil, and buy cheap store brand ( walmart or kendal is cheapest ) 10w30 full synthetic oil and run her with that.

I have 2 tractors I am running on full syn oil after having stuck valves ( after I did head work ), and they are purring like a kitten.

 

[Soundguy]

forgot to mention.. it is always possible you have a bad valve spring too.. that takes a little more work to check... so if the atf or syn oil don't help.. you just might have abad spring.

 

[seth350]

Thanks soundguy, I will give that a try. New problem starting with the tractor now is it doesn't respond well with load changes. Even letting out on the clutch has to be very gradual or it will stall. Even a small change in incline of ground will cause it to stumble. It will only recrank if you jack the throttle lever back and forth. I'm thinking I may have dusted off some cobwebs that were holding something together, as I have been pulling up some crape myrtles last couple of days and doing some ground leveling. Funny how these old irons have such a sense of humor.

 

[Soundguy]

check to make sure nothing is jambing the governor rod and linkage to the carb. ( left front of the engine. )

something may be bent / binding.. maybee a branch stuck in there..... etc. seen that before..