Help! Make my crank b start easy
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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=158893
Printed Date: 19 Aug 2025 at 11:13pm
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Topic: Help! Make my crank b start easy
Posted By: ryanschott
Subject: Help! Make my crank b start easy
Date Posted: 09 Mar 2019 at 6:21am
| I have a 1938 b crank start with fresh engine it is aweful to get started or to start at all. What things could I do to make easier to start. I had a 1939 b and you could crank it three times and would always start. What do I need to do. Has new plugs, good compression, runs awesome when you get it started. Have timing so it will fire early ( mage rolled close to motor ) new gas |
Replies:
Posted By: 2011dandd
Date Posted: 09 Mar 2019 at 7:40am
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Does yours also kick back on you a lot? Mine does and symptoms sound exactly the same. I love the tractor it’s great but I hate bloody starting it |
Posted By: steve(ill)
Date Posted: 09 Mar 2019 at 8:05am
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setting the mag " close to the motor" aint good enough. You need to roll the motor over slowly until the mag SNAPS, then look thru the timing hole and see if the crank is on the FIRE mark... take the plugs out to get it to roll easier. ------------- Like them all, but love the "B"s. |
Posted By: DaveKamp
Date Posted: 09 Mar 2019 at 8:43am
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Steve's right- you certainly DON'T don't want it to 'fire early'... it needs to be set per the book... no special tools, just follow the instructions. The magneto has an IMPULSE COUPLING... when you turn the engine slow, there's a clock spring that winds up, and when the crank gets past TDC, the spring latch is tripped, causing the coupling to go CLACK... when that happens, you get a nasty hot spark.With the crank being PAST tdc, it pushes the crank in the proper direction, causing it to start easy. If you set it way early, it will fire AT or BEFORE TDC, risking serious damage to you, and possibly the engine... so read the manual, set it per the instructions. Next... how's your float bowl height? if too low, or too high, it won't play ball. How's your oil-bath air cleaner? Can't have water frozen in the bottom... How's your valve clearances? If you set them tight, it won't be happy with you. Did you inspect the intake/exhaust manifold? Seal at the block must be tight, and there must NOT be a crack between intake and exhaust sides... and the vacuum port must be sealed properly. The exhaust manifold and muffler CANNOT be plugged full of mouse mess and mud dauber clods. If you've rebuilt the engine, get the timing set right, take it out and run it up and down some hills... get the rings seated, retorque the head, recheck valve clearances. When a magneto/carb engine is set right, all it takes, is to push it just past TDC gently with the crank, on a cylinder that has fuel and air. My '38 B takes exactly three 180 degree pulls on the handle to start... because that's what it takes to get a dry engine one freshly charged cylinder. ------------- Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest. |
Posted By: Dick L
Date Posted: 09 Mar 2019 at 3:15pm
| Turning it over slowly and stopping when it snaps is called static timing and then the TDC should be in the inspection hole. Running at full throttle and checking in the inspection hole with a timing light you should see the FIRE line to be in time. All engines are static timed to TDC. Car Truck or tractor. Proper advance is set while running. |
Posted By: CrestonM
Date Posted: 09 Mar 2019 at 3:39pm
| I agree with the others. Reset your timing. My "B" used to kick back something awful, and that scared me away from cranking it. I readjusted the timing to TDC, and now it starts like a dream. I have electric start, but I seldom use it. It usually busts off on the 2nd or 3rd pull when cold, and today it started on the first after having sat for 3 weeks. |
Posted By: mdm1
Date Posted: 09 Mar 2019 at 4:37pm
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I have a 39 B that I hated until I learned how it wanted to be started. If I remember I set it to click when the pulley bolt was at 12 o clock on the compression stroke of #1 cylinder. I cannot find any marks on the flywheel. I choke mine and have the throttle at 1/4-1/3. I have to crank it a few times to get the cylinder primed. I have rebuilt my cylinder head also. Make sure you have enough gas in it. You will learn when it is going to start by the feel when you crank it. Hope this kinda makes sense and not nonsense. ROD (NH) has a good page on his website about timing the mag. Good luck.
------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: ryanschott
Date Posted: 09 Mar 2019 at 5:27pm
| I shall try all these good ideas tomorrow. It never kicks so haven’t had that problem. Hopefully it has fire of f or something on the flywheel I have had a few the had nothing on them. Turning mag away from block ( clock wise if looking at it from seat) will retard the spark and make it fire later? |
Posted By: ryanschott
Date Posted: 09 Mar 2019 at 5:31pm
Also manifold is sealed good and lack of air cleaner means that’s not plugged 
|
Posted By: Gerald J.
Date Posted: 09 Mar 2019 at 5:50pm
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Shop manual should have details. http://geraldj.networkiowa.com/Trees/Allis-Chalmers-G-B-C-CA-Service.pdf" rel="nofollow - http://geraldj.networkiowa.com/Trees/Allis-Chalmers-G-B-C-CA-Service.pdf Gerald J. |
Posted By: john(MI)
Date Posted: 09 Mar 2019 at 8:18pm
Going back to your original post. I would change the torque tube to one that takes a starter. If you don't want to go that route, then I would always keep someone on hand to help pull start it! ------------- D14, D17, 5020, 612H, CASE 446 |
Posted By: ryanschott
Date Posted: 09 Mar 2019 at 11:17pm
| Retarded the timing a bunch and it started up easy three times with only two cranks each. |
Posted By: 2011dandd
Date Posted: 10 Mar 2019 at 6:15am
This all sounds like great advice. I will check all of these things once I have read and fully understand the manual. What is the zenith carb float height by the way? |
DaveKamp wrote:Posted By: Steve in NJ
Date Posted: 10 Mar 2019 at 8:21am
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That cranking by hand crap is for the birds. Besides, the older you get, the older that gets! Like John (MI) says, torque tube change, add a Starter motor, sore arm and back pain gone. Tractor starts right up! Can ya tell I'm gettin' older? LOL! Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: Jim.ME
Date Posted: 10 Mar 2019 at 8:41am
| For your carb settings and adjustments check out pages 26 and 27 of the B-C section of the manual Gerald posted. You may want to download and print a copy of it for reference. |
Posted By: Dick L
Date Posted: 10 Mar 2019 at 9:40am
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Measure if you want but really not necessary to use a rule. All the years I have been working on these Zenith carburetors I have never measured the float settings. When holding the top up side down and the float is parallel with the base it is in adjustment. 
|
Posted By: Leon n/c AR.
Date Posted: 10 Mar 2019 at 11:43am
| Like Dick L said works good. Done it like that for years on many different carburetors. Leon |
Posted By: ryanschott
Date Posted: 10 Mar 2019 at 6:11pm
| Thanks everyone went out today and three cranks and it was running. I’m going to work on getting my 1940 b to start that good but have to get a gas tank fixed and a new water pump |
Posted By: Dick L
Date Posted: 10 Mar 2019 at 6:16pm
| Good Deal! |
Posted By: mdm1
Date Posted: 10 Mar 2019 at 6:34pm
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One gets great satisfaction getting them to work how they should! Good job and good luck! ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: WD45Diesel57
Date Posted: 11 Mar 2019 at 7:35am
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when I freshened up my 38 B engine I couldn't get it to fire by hand, everything was set correctly but motor was just cold and stiff. so I got my dad to tow it and it fired right off and now that the motor has run in alittle it cranks on the second pull of the crank! Ive never used timing marks I set it close as I can and go by ear once its running! ------------- 1-B's, 2-C, 2-CA's,2-WF, 1-WC,1-G, 3-WD's, 2-WD45, 1-RC, 1-D17 Diesel, 1-D14, 2-D15,1-D17 row crop,1-D19 gas and All Crop 40,60,66,72,90 and 100 |
Posted By: ac fleet
Date Posted: 11 Mar 2019 at 11:52am
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Well,----I have yet to find any marks on any of my b's, or c's. the flywheels just are not marked. Have had people with good eyes look while turning slow by hand and no marks show up in the hole. thanks; ac fleet ------------- http://machinebuildersnetwork.com/ |
Posted By: Dick L
Date Posted: 11 Mar 2019 at 3:24pm
| ac fleet, Go to the hardware store and get a stiff wire wheel brush with a 1/4" shank. With the engine running with the drill running put it in the inspection hole and clean the flywheel to shinny metal and see what you have. The stiff brush will not clean out the stamping. The spinning stiff brush will not catch on anything to cause a problem. |
Posted By: mdm1
Date Posted: 11 Mar 2019 at 6:12pm
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I have only checked one B for any marks. Found none. Will try your idea next time Dick. ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: SteveM C/IL
Date Posted: 11 Mar 2019 at 9:33pm
| don't know about "B's" but the marks on my 45 are slight. |
Posted By: steve(ill)
Date Posted: 11 Mar 2019 at 9:51pm
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I have several Bs and every one had a Fire and TDC mark on them... Some are very faint as Dick said and need cleaned... THen I put a red paint mark on them after cleaning......... And I miss spoke a few days ago saying static timing was at the FIRE mark. Of course it is TDC as Dick had said.............. late night or CRS setting in ? ------------- Like them all, but love the "B"s. |
Posted By: Dick L
Date Posted: 12 Mar 2019 at 5:59am
I had the same type brain freeze over on YT a while back. Happens to everyone. |
Posted By: ac fleet
Date Posted: 12 Mar 2019 at 4:40pm
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I have a brush and drill. I will try your method when it warms up and mud gets a bit drier! thanks! ------------- http://machinebuildersnetwork.com/ |
Posted By: Dick L
Date Posted: 12 Mar 2019 at 5:25pm
You Have Mud?? Me to! I had to feed hay early this morning while the ground was still frozen. This evening I had to use my walker cart to take water out. The wheelchair tires on it cut in about an inch and a half. Very hard to push with two pails of water. |
Posted By: ac fleet
Date Posted: 13 Mar 2019 at 6:06pm
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Ya! ---it's getting deeper too. they say high wind heading this way, its blowing strong already. Went to start one of the C's, and it will only start/run with jumper wire direct from batt. Wont spark at all going thru the resistor. Tried 3 different coils and resistors, still same o. It will only run 15 mins. or so then just die. Won't start for about 3 hours or overnight. same thing again when it does start. WD's and 45's of mine are wired the same way and never refuse to start. What's up with the C? thanks; ac fleet ------------- http://machinebuildersnetwork.com/ |