allis B presents a new problem

My 47 B has been with me for almost 25 years. It has a woods belly mower under it and that is pretty much all I use it for. I have worked it hard mowing at times and it has always taken what I throw at it. In the deal when I purchased it, the tractor came with an extra (fresh rebuild) motor on a skid that I have never needed. I have never had any major engine problems. Other than radiator replacement, mag work, starter work and some wires, I pretty much have not had to do anything. Recently it was mowing along and began to bog down to the point that I thought I could hear the pistons knock and then it quit. It was not running hot and the oil pressure was reading. After cooling, it started back up and I have used it most of the summer. I have changed the oil and did put a new style (NAPA) filter on it after the first bog that I had and read afterward that there might be pressure problems associated with those. I did notice that the gauge does bounce quite a bit while mowing. I have been running Shell 15-40 diesel and a C159 for years without any issues. I took off the NAPA and went back to the Fram C159 and Shell Rotella T1 30 WT that also says diesel oil. Neither one is listed as detergent or not, that I can see. Now today, I am mowing and working it in some light and some moderate growth, but by no means very hard. I am mowing on a flat level area and again the bogging down to the point it quits. now it is sitting behind the barn cooling. just before it quit I noticed there was oil pressure and was in the normal operating temp on the gauge although the oil was very warm. I will say that after switching over to the straight wt. the gauge is much more stable and does not bounce nearly as much if at all. If I left something out, let me know. I was wondering what might be happening to the old girl. Where should I start?
 
As with any engine that dies like that you check the spark the moment it dies and then fuel flow at the carb drain plug.

Spark needs to be a blue/white that jumps a 1/4 inch gap or more.

As for fuel flow you need a good steady flow of gas that will fill a pint jar in less then 3 minutes.

As long as the engine is not locking up as in when it dies you can turn it over by hand not likely to be an oil problem
 

Don't count out the engine..it may be a Condenser, Coil or fuel flow problem...

It may take a few attempts to cure the problem and that is normal..!
 
Will the starter crank the engine immediately after it quits? If it will not turn over immediately it most likely is a bearing that has gone bad. A bearing going out on this engine will not effect the oil pressure. If it will spin over then your to what old said that spark and fuel flow needs to be checked.
 
Alright. I will get it back mowing tomorrow and be ready to check spark, fuel and being free right after it dies again. I just cleaned the sediment bowl and it seems to fill the cleaned bowl as quickly as always. I did also put a new gasket in there this cleaning and the screen was clean. I will check the flow at the carb with a jar. I usually can catch bubbles in the bowl if I am low on gas and on a hill or under load if it sputters. In this case I just filled the tank. I will take all your suggestions and see what happens over the weekend. Thank you
 
I will be very interested in hearing about your findings after mowing tomorrow. I'd like to know if the engine is hard to turn over by starter or hand crank. If the engine is binding when it stalls it could be the same as what happened to mine. The damage occurred in the previous ownership. The block was plugged full of crud around the #4 liner to the point that it had no chance to cool. The piston got so hot that it started binding...was blue and scratched. The liner had got so hot that with the crankcase oil cooling the liner skirt the temperature difference was too drastic and the liner skirt broke off in pieces and collected at the bottom of the pan. At this point coolant was leaking into the oil. That's how I bought the '48 B, I have fixed it now and it runs perfect. There was no damage to the bearings thankfully. If your engine is hard to turn over hot I wouldn't run it warm again to simply keep the repair bill cheaper. It's understandable that an engine block can use flushing after nearly 70 years of service.
 
I am hoping to get it through one more month which could equate to only one more mowing. I could do it in smaller pieces and never let it get too warm. Then it will be a long overdue park in the shed and a good look over the winter. How did you handle the flushing? I seem to recall the use of ATF in the crankcase for a short while and an oil change after. I was also reading about vertical mufflers and ATF and under the plugs although it does not smoke at all through the exhaust. I would suspect the rings are fine. It has a compression test in its near future to determine that. Any thoughts on the use of ATF?
 
Make sure the fuel tank is venting. If it isn't it will only let fuel out for a while, then the fuel flow will slow and stop.
 
ATF is very good for flushing the lubrication system and crankcase because of the effective detergents it contains. However, the flushing I was referring to earlier is about flushing the block where all the coolant circulates. For me it was quite easy when I had #4 liner removed but you can access the block through the coolant holes on top once the head is removed. If you stick a pressure washer nozzle into those cooling holes with the block drain plug removed (it's best to remove the carburetor) you will have the crud coming out. The use of a metal rod into the the drain hole as well as down the block helps loosen everything for coming out. It's best with the lower rad hose removed also.
 
I noticed when it stalled a small amount of steam/smoke near the carb and the oil was smoking (hot) through the breather but the temp was in the normal range and went no higher than normal. If cooling would cause the bogging and stalling, I noticed some time ago that the radiator was clogged on the lower end but since I have not seen the temps rise I was waiting to clean that until I retire it for the year. I will clean that out now and see if those temps stay down. Are you suggesting that the temp or the coolant had anything to do with the bogging and stalling?
 
If it is in fact over heating that can/will cause an engine to bog down and stall and can even cause an engine to lock up till cooled down. But I would also think you could here the radiator boiling unless you did not listen well. You gauge may not be reading correctly and it could well be getting to hot
 
In the case of my engine with liner #4 totally "clogged in" the coolant could not circulate at all at the back of the block with virtually no way for the piston to get cooled. This would have very little effect on the temperature gauge reading.
 
I never heard the radiator boiling or making any sounds at all. I see a small amount of residue (metal or non water) in the bowl but that may be nothing more than material from changing the gasket. I had to scrape the old one out. I will clean it, and test for good flow at the carb first. Then on to the cooling system. I started the cooled engine just fine and got it back to the house. I noticed the radiator is clogged a bit at the bottom but I don't think enough to cause a problem. I will clean that out before running it. I will try to get some digital temps on the radiator to see if they are running higher and I can also hit different parts of the block. I hope those two will put things back in order, especially right if it stalls again. I also noticed the belt is a little loose and maybe the fan was slipping and not cooling properly. It wasn't squeaking though and that will be adjusted too. I will check the cooling system amount for a good mix and adjust that if necessary too. The last round of maintenance I did was a part of the cooling system that cracked when my anti freeze was not adjusted correctly but that was fixed last year. I have it parked under a shade tree and will take care of these three things, and see what happens
 
It has been raining everyday here since Saturday so I have not been able to mow. I took care of everything we talked about with the exception of pulling the carb fuel plug. As soon as it dries up a bit, I will put it back in the grass.
 
finally after a week or more of waiting for dry weather, I put the B to work. I have run it twice for extended periods (two hours) and had no repeat of the problem. Hard to say which thing corrected my problem or if it is corrected at all. Intermittent problems are hard to diagnose. I took care of everything mentioned but I did not take off the carb. I am waiting to park it for the season to do that. Until my problem returns or the season ends, I am back in the grass. Thanks for all the suggestions.
 

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