slow cranking

[imported_alex_G]

hello all,

I have Murray garden tractor with 18.5 HP Briggs and Stratton engine 42A707-2653.
I was filling gas a day ago and accidentally spilled gas on the engine. A decided to let it dry.
Now it doesn't start. It spins engine slowly for a rotation and then stops. I disconnected everything and connected starter right to the car engine.
Same result - spins slowly and stops spins and stop. I removed starter from the tractor and tried same procedure. Started spins fine and fast. I tried to spin engine with hands to make sure it's fine. I can rotate engine just fine.
Is this a starter problem or it can be something else?

Thank you,

Alex

 

[WizeOne]

Re: slow cranking

I really doubt it had anything to do with the spilled gasoline. I would suspect that it had to do with the starter motor's inability to develope proper torque. Does it have a pull start rope?

 

[imported_alex_G]

Re: slow cranking

It doesn't. I just made a small test - I removed spark plugs and it spins fine.
So it's not the starter then. What can cause it?

 

[puddle jumper]

Re: slow cranking

It sounds like you have a bad conection on the starter.

 

[WizeOne]

Re: slow cranking

It sounds like you have a bad conection on the starter.

Good point pj. Most likely corrosion on the battery terminals. Starter works with no load, plugs out or starter off the engine, but won't crank with compression load? Dirty connections!!

 

[imported_alex_G]

Re: slow cranking

It wouldn't even start if I disconnect starter and connect it to the car.
I would think bad starter but it spins fine with spark plugs out.

 

[mla2ofus]

Re: slow cranking

Assuming this is an overhead valve engine, the valve lash probably needs setting. Most OPE engines have a built in compression release and if the lash is too great the engine will crank just as you describe.
Mike

 

[Nandy]

Re: slow cranking

I am no expert at tractors but I have been working in car motors since I was 16. Anyway, when you take the plugs out of the motor there is no compression. That will make the motor very easy to turn. You take the starter out and it seems to work fine, that only tells me the starter is not strong enough for the load. Either because there is a bad connection, brushes are worn or something else. I would chase the starter first...

 

[imported_alex_G]

Re: slow cranking

That's the problem - I can't find exhaust valve on the diagram or owner manual.

 

[Splat]

Re: slow cranking

Bad compression release is first to come to mind. As MLA2 stated the briggs engines were notorious for this. Infact Briggs had a recall on the cams because of this problem. I'm trying to remember the model number that was included in the recall.

42a707? This is an opposed twin if I remember correctly, and I don't believe they had a compression release. What year was the engine manufactured? this will be the first 2 numbers in the date code will be the year. 93XXXXXX would be manufactured in 1993 for example.

Couple things that come to mind. Is this a hydrostatic transmission on this? Hydro will always be engaged with the engine, and when It's a little chilly out the fluid becomes thick and is just that much more for the starter to crank. Also you have to remember the cold weather causes the oil in the engine to become thicker and harder for the engine to turn.

When you removed the spark plugs and cranked the engine did fuel come pouring out the cylinder? You could have a bad needle seat in the carborator and thus causing raw fuel to leak into the cylinder. Fluid cannot be compressed and thus you get hydro lock. Check the fuel in the tank today and make sure it's at the same level as when you filled the engine yesterday. Also check the oil and make sure it's not abnormally high due to dilution from washdown with fuel from the cylinder.

Even if the starter spins when off the engine, the stator inside can be worn and causing a weak motor/high amperage draw. You would have to check the amperage draw off the engine. Anything over 30-40 amps it's bad.

Bill

 

[Splat]

Re: slow cranking

The valves are on page 3. Reference numbers 33 and 34. But the lash won't be listed in the parts break down. I can't remember it off hand for the opposed twins, if you need it I'll look it up tomorrow when I go to work in the tech book. I'm going to need the date code tho.

Bill

691794 Exhaust
691804 Intake

 

[imported_alex_G]

Re: slow cranking

Here the code 97101358.
I have oil 5X30. I had no problem to start it in cold weather. At least motor was spinning. I suspect bad starter but it spins engine with spark plugs out.

 

[rwise]

Re: slow cranking

I picked up a heavy duty starter from ebay for mine cheaper than the starter cost local. But mine would spin, just not fast enuf to start,,, put the starter on it fired up and I gave the mower away!

 

[dolluper]

Re: slow cranking

Check your air gap or that there is no rust on flywheel....will pull down ANY STARTER or battery