B running rough--fuel filter cavitation
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=14929
Printed Date: 03 Feb 2025 at 4:56pm
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Topic: B running rough--fuel filter cavitation
Posted By: trhod12
Subject: B running rough--fuel filter cavitation
Date Posted: 09 Jul 2010 at 12:21am
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My B has been starting very rough, and seems to sputter alittle when under load (brushhog running and moving up hill).
In the spring I did a tune up (points adjusted, plugs, wires, etc) and it was running really good, until the past couple of weeks. It seems like I need to do another tune up.
One thing that i noticed the last time I used the B, when I went to start the tractor the fuel filter had cavitated (look like someone took a coke can and sucked all the air out of it till the sides caved in). I was able to grab the fuel filter and squeeze the edges until it popped back out.
When I was brushogging the last time, I notice that in the fuel filter I had bubbles and the filter was not filling all the way up. I also notice that in the sediment bowl I was getting bubbles. It seems like it is a vapor lock.
Any thoughts on what is going on, or (more importantly) what I need to do to fix this.
I have been toying w/ the idea of going to the electric ignition and going away from the points. Any thoughts on this conversion???
Thanks,
TRHOD
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Replies:
Posted By: Gerald J.
Date Posted: 09 Jul 2010 at 10:33am
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The in line filter didn't come from AC with the tractor. Its likely a plastic filter made for automotive service where there is a fuel pump to supply enough pressure to push througho the fine screen. Your tractor will run better if you replace it with a piece of tubing or the filter for a gravity fed engine, like one for a Briggs engine that will flow more freely. Also check the tank for floating stuff blocking the sediment bowl inlet screen inside the tank. Ignition has nothing to do with fuel starvation. There are many testimonials about how good the electronic ignitions start, and a few about how expensive they were when the failed. There are 4 parts in the standard system, and at least ten times as many in the electronics which makes the odds of failure higher for the electronic system. And for the price of one electronic system I can buy more than sets of points and condenser and on my tractors I've only had to change them once in ten or 20 years. It is important to keep a bit of cam grease on the cam and a tiniest bit of oil on the point's pivot, and more oil in the felt under the distributor rotor to lubricate the centrifugal advance parts. Gerald J. |
Posted By: pumpkin man
Date Posted: 09 Jul 2010 at 1:00pm
| check the gas cap it must have a vent hole of some sort also check the air clener cup with al the rain weved had water gets in some how in the shed or parked outside plus the P-water thay call gas today dont help anything run good |
Posted By: CTuckerNWIL
Date Posted: 09 Jul 2010 at 1:05pm
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It sounds to me like your vented gas cap might not be venting. I would put a new screen in the sediment bowl and throw away the add on filter and replace steel tubing from sediment bowl to carb. Sediment bowls worked fine for the last 50 years. Make sure the tank is clean and the gas cap vent works. If you have rust in the tank a temporary fix is to add a short stand pipe to the top of the sediment bowl base but if it continues, the fix would be to clean and line the tank with Red Kote or some such tank liner.
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: trhod12
Date Posted: 09 Jul 2010 at 10:39pm
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I've been running high octane gas 92 or 93 to try and help out with the gas problem.
I tried running the tractor with the gas cap off, and it still was bubbling.
I will check the air cleaner for water, and the gas tank for junk. The tractor had a fuel filter on it when I bought it last year. If the above doesn't work, I will try removing the filter and running a straight piece of fuel line.
Thanks for the ideas.
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Posted By: Gerald J.
Date Posted: 10 Jul 2010 at 12:00am
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High octane gas won't help a low compression engine for anything. It may hurt by needing a different mixture to burn well. High octane reduces the tendency of lean mixtures to ping in high compression engines. The filter is definitely a problem and not needed. Junk in the tank is a strong possibility. Gerald J. |
Posted By: realolman
Date Posted: 10 Jul 2010 at 8:00am
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I don't know anything about a B... maybe it doesn't even have a fuel pump... I don't know , but one time I had a fuel pump that formed a ring of varnish around a valve and then the ring came loose and stuck under the valve....looked like a little hemlock needle.... thing drove me nuts till I found it. The fuel filter would be empty, so I thought sure the tank/ line was plugged.... but it never was. Took it off and cleaned it... put on a new fuel line.... the fuel pump / varnish pine needle would apparently push the fuel back up into the tank.... but it would run fine for an hour or so, and when I let it sit, the fuel would fill everything back up by gravity.
Having said that... it doesn't explain anything about your fuel filter sucking shut... that seems to indicate a plugged fuel line / tank.... and a very good fuel pump.
Guy tells me that the gas used these days is hard on fuel lines... maybe the line is collapsing somewhere.
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Posted By: T.J.-N.J.
Date Posted: 10 Jul 2010 at 8:42am
| Did this tractor sit for a while before you got it ? I remember when we got our Farmall Cub Lo-Boy it had sat for 8 or 9 years with gas in it no matter how good I flushed the tank and cleaned the carb it kept plugging up with gunk,lasted almost the first whole season Heat from working,strong new gas and vibration kept loosening up stuff from all the nooks and crannies in the fuel system. By the end of the summer I could tear down that carb wash it out and be back mowing in about 20 minutes I put Stabil in every can of gas I buy and havent had any problems with it in years. Check that the cap still vents and I would put a Briggs filter on it in place of the other one to catch any junk coming out of the tank before it gets to the carb at least for a while like the other post said. T.J. |
Posted By: Brian Jasper co. Ia
Date Posted: 10 Jul 2010 at 2:34pm
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I had similar problems with my CA when I first bought it. It didn't have an added filter, but I kept getting dirt in the carb plugging it up. I got to be like TJ and got really good at tearing the carb apart and back running in short order. What I found was the hard, crusty stuff that is left behind after old gas has dried up was inside the fuel line after the filter was coming loose and plugging the carb. I bought a new sediment bowl assy and bent a new piece of steel line to the carb and haven't had to fool with it going on 14 years now.
As far as electronic ignition goes, I have both an Oliver 60 and CA Allis converted to electronic. Electronic ignition allows for larger plug gaps. I find both tractors start easier and run smoother now than when they had points. ------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: LouSWPA
Date Posted: 10 Jul 2010 at 2:56pm
Na' no fuel pump, just good ol' gravity! ------------- I am still confident of this; I will see the goodness of the Lord in the land of the living. Wait for the Lord; be strong and take heart and wait for the Lord. Ps 27 |
realolman wrote:Posted By: trhod12
Date Posted: 10 Jul 2010 at 11:04pm
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TJ, I don't know how long or if the tractor sat for an extended period of time before I got it.
I got the tractor about this time last year, and really didn't have any problems w/ it until I got caught this spring time with the tractor sitting outside by mother nature with a snow storm. That was when I did the tune up (plugs, wires, points) and it ran better than every until a couple of weeks ago. In the springtime, when I did the tune up, I change the entire fuel line from the tank to the carb, and put a new fuel filter on at this time. Like I said, I have run it since springtime w/ this setup, and up until the last couple of weeks, it was running like a champ.
I used fuel stabilizer over the winter to store the tractor, but I have not added any stabilizer since spring time. I have been using between 6-12gal of gas every 2 weeks since the springtime, so I didn't think I would need it.
Again, thanks for all your thoughts on this. I'm not gonna get a change to look at the B until late this week, but it sure helps to have some ideas of what to try when I head to the farm next.
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