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B&S 18hp Cranking Slow


dfs's Avatar
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11-17-06, 10:14 AM   #1  
B&S 18hp Cranking Slow

I have a B&S 18hp Twin #42A707 (1997) electric start. I have read 22 pages of previous posts but I am still confused. Here is the problem: Turn the key and the flywheel will turn about a half revolution and stop and continue like that but not start. I tried a new battery but no change. I used jumper cables from the battery to the starter but no change. Removed the starter, connected to the battery and it runs ok. I was reading about the valves needing adjustment. Removed the valve cover and an access plate (for the valve springs) but did not see where they could be adjusted. Now I am lost and need new gaskets. Any Ideas?
Thanks, Duane

 
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11-17-06, 12:58 PM   #2  
The valves in your engine must be removed and the stem's ground to adjust the valve clearance. This in probably not the problem in your case.

Most likely it is a problem with insufficient current being supplied to your starter. Check and make sure all connections and cables are good, clean and tight. Clean any corrosion from cable ends and make sure they are tight. Clean the ground cable where it connects to the frame and make sure it is also tight. Make sure the engine has a good ground to the chassis. In some cases resistance can build up in the cables where the cable ends are crimped on as moisture can enter and corrosion can occur, it the ends have a lot of build up, it may be necessary to cut the old connectors off and replace with new ones.

 
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11-17-06, 01:27 PM   #3  
Thanks, I do need to check the connections. Those are things you don't think about until you have a problem, although when I used jumper cables from the battery direct to the starter, I had the same problem.

 
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11-17-06, 02:03 PM   #4  
checked the oil?

I ran across the same type thing once that was caused by fuel draining into the oil sump. Maybe check the oil for level and/or gas, espicially after jumping straight to the starter and getting the same symptoms.

 
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11-17-06, 02:22 PM   #5  
There is a possibility that the problem is being caused by fluid in your cylinders. Remove the spark plug and try cranking the engine, if it spins good without the plugs, check for fuel, water or oil in the cylinders, and check your oil make sure it is not contaminated with gas or water and is at the proper level.

When cranking your engine without the spark plugs be sure that the plug leads are grounded or placed where they will not arc and start a fire.

 
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11-17-06, 03:37 PM   #6  
switch?

could it be a key switch bad?? ive heard of it in the past..

 
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11-17-06, 03:41 PM   #7  
Azis
If it does at least engage the starter then the key switch and other components should be ok. Connections as 30yr explained are prolly the cause. If you try it with the spark plugs removed and it still spins slow then even more towards connections.

 
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11-17-06, 05:13 PM   #8  
If the starter "spins OK" with it off the engine doesn't mean it's in good condition. It could have a worn bushing on one or both ends which could make it drag while cranking engine. If you don't find anything wrong w/ engine, I'd have the starter checked out.
JMHO,
Mike

 
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11-19-06, 04:15 PM   #9  
I am guessing it's the starter, oredered a new one, should be here in a couple of days.

 
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11-19-06, 07:25 PM   #10  
Sounds like it probably is the starter, but usually it doesn't require replacement...just a new bushing at the end cap (less than $5). This engine requires a lot of torque from the starter, and the end cap bushing wears faster on starters on these twin engines because of the force applied to it. When the bushing wears, the starter shaft rides away from the flywheel teeth a bit until the armature begins to scrub the field magnets in the starter case, which creates too much drag for the starter to operate.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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11-20-06, 05:24 AM   #11  
If the starter was the problem,save the old one,have it repaired or DIY it. Then you'll have a spare.It won't take up much storage space.
Mike

 
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11-21-06, 04:54 PM   #12  
All is well. It was the starter, wow what a difference. Fires right up and sounds better, plus I cleaned the carbon off the cylinders and valves.
Thanks for all the help!!

 
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01-26-07, 01:11 PM   #13  
similar problem...

I just got a tractor with the same engine and it too turns over rather hard. The main reason is that the tractor is stored in an unheated shed and it's sub-zero temperature where I live. However, while I tried starting the engine, I noticed smoke coming from the starter. I let it cool and tried it later. It still works great, but do you think the bushing in the starter somebody mentioned earlier needs to be replaced? (engine is about 4 years old)

I brought the tractor into a heated room for a while and it started with no trouble. Still, I'm concerned about that smoke from the starter.

 
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01-26-07, 03:45 PM   #14  
msidan;
Anytime something electrical smokes it is time for concern. Fix it before you have to replace it, fixin is usually cheaper. It's gonna fail sometime and as with Murphy's Law it's going to be when you need it most. The tough cranking could be the oil bein cold, a lot of people run strainght 30w in their lawn equipment and 30w oil is like tar when cold. Have a nice day. Geo

 
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01-26-07, 10:54 PM   #15  
I think you're ok...the cold is probably what made it hard to start in the first place. If you damaged the starter, it wouldn't be working fine in the heated room.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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