WD45 Motor Problem
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=196078
Printed Date: 12 Nov 2025 at 2:00pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: WD45 Motor Problem
Posted By: Gary Burnett
Subject: WD45 Motor Problem
Date Posted: 09 Jul 2023 at 7:12pm
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Just bought a nice looking WD45,power steering,57 model,4 bolt WF,new tires all around.Here is the problem the motor turns over hard even on 12V battery plus a big jump box,seems to have too much compression or other issue.Supposedly was rebuilt about 4 years ago,all this from the seller which wasn't the person who was fixing it up.Where do I go from here with it? |
Replies:
Posted By: DrAllis
Date Posted: 09 Jul 2023 at 7:36pm
| So, attempt to run a compression test with all spark plugs removed, throttle wide open and a battery charger on the battery. 125 psi is WD45......145 psi is D-17 compression.......170psi or more is 170/175 compression. |
Posted By: WF owner
Date Posted: 09 Jul 2023 at 7:47pm
| Does it turn over hard with the spark plugs removed? Maybe not enough bearing clearance? |
Posted By: Gary Burnett
Date Posted: 09 Jul 2023 at 8:00pm
Turns over fine with no plugs
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WF owner wrote:Posted By: DrAllis
Date Posted: 09 Jul 2023 at 8:29pm
| I've built several pulling engines in that chassis with 350+ cubes and 260 psi compression and always got them to start with a healthy 6 volt WD-45 3 bearing starter on 12 volts. 3 brg and healthy is the key along with large enough battery cables. |
Posted By: Gary Burnett
Date Posted: 10 Jul 2023 at 10:22am
| Checked compression No.1 and 3 right a 145.No 2 125 but No.4 is 175 checked and double checked that one. |
Posted By: JC-WI
Date Posted: 10 Jul 2023 at 10:51am
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Check your starter out for the torque it can produce. Check your battery out too... plus check ALL connections and put on heavy gauge wire if you got some cable that is for 12 volt cars already on the tractor. Got a WD that turns slow, always turned slow. Dad had it to the repair shop and they checked it out and put a new end cap on and brushes... and still turned slow. Been a slow starter since I can remember it 65 years ago. Maybe it was just a slow starter to begin with? All the other WD's and 45 turned much faster than this one did. Never tried using 12 volts on it since the tractor has a solenoid on it for LP gas. Don't want to burn that bugger out cuzz it probably is obsoleted for the last 40 years. ------------- He who says there is no evil has already deceived himself The truth is the truth, sugar coated or not. Trawler II says, "Remember that." |
Posted By: DrAllis
Date Posted: 10 Jul 2023 at 11:06am
| Most WC's and WD's only had a bushing on each end of the starter armature. A good WD45 starter has a CENTER bearing making it start higher compression engines easier than a two bearing starter. |
Posted By: Gary Burnett
Date Posted: 10 Jul 2023 at 2:54pm
| So wonder why the #4 compression is so high? |
Posted By: Ed (Ont)
Date Posted: 10 Jul 2023 at 6:31pm
| Ya that is a bit high. Maybe carboned up. But would have to have a fair bit of stuff in there to bring it to 175??? |
Posted By: steve(ill)
Date Posted: 10 Jul 2023 at 6:37pm
makes ya wonder if all 4 pistons are the same ?? 
after checking out ALL the cable ends... i would try another starter motor, if you have a spare. ------------- Like them all, but love the "B"s. |
Posted By: WF owner
Date Posted: 11 Jul 2023 at 3:19am
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Have you tried hand cranking it? If you have ever cranked many of these, hand cranking should let you know if it is turning over abnormally hard. The first thing I would do is load test the battery. Even with a jump starter, a battery can raise problems if it has an internal problem/ If the battery tests good, I would start looking over the battery cables. Are the battery connections good and clean? Clean up the end of the ground cable and make it is clean and tight. Make sure the cable to the starter is also clean and tight. Does it still have the pull button start or has someone converted it to a relay (solenoid) start? If it has the pull button, remove it and clean up the inside connections. If all this is ok, I think it pretty much eliminates everything but a bad starter.
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