Think I diagnosed wrong!

[dart451]

Working on a Craftsman tractor, 917.275821...charged battery although it was 4 years old, it would start engine if you held the key to start for several seconds...acted like a dead battery. Bought new battery, does the exact same thing. Thought, maybe bad ground or solenoid. So, I took my battery jumper and found a good ground and touched the positive side of starter with positive lead. Does the same thing! So, that's bypassing a bad ground, solenoid I would think. Sound like a starter to you guys??

[RoyM]

That is the only thing left.

[dart451]

That is the only thing left.

That was my thought...but God knows I've heard other strange things that cause things not to work...lol

[38racing]

Assuming that the engine is well grounded to the chassis. I've had engine bolts loosen.

[dart451]

Well, just when I thought I had it all figured out...I DON'T! Put on a new starter, even one of my used ones would do the same thing. The new starter started it no problem! However, when I got it back to the owners property, it started doing the old dead battery again! ARGGG! Before I put on the new starter, I also put another ground on the battery to make sure it wasn't a bad ground...all the engine bolts are nice and tight! When I take out the spark plug, it turns over no problem, it's the compression stroke it's having trouble with! And it has damn good compression! Not sure exactly what to do at this point. If you hold the key on for a few moments, it will turn over and start. I've told the owner to give me a call if it will not start and I'll fix it for free...(If I can find out what the hell is wrong with it!)...

[KE4AVB]

31P777-0296-E1

You should only have 70-90 psi with the ACR working.

It probably either the valves are out adjustment or the ACR on the camshaft has failed. 793880 camshafts are bad for this to happen to them. Non invasive test consists of the checking the valve clearances and looking for the ACR bump on the intake valve as the engine approaches TDC compression stroke.

[dart451]

31P777-0296-E1

You should only have 70-90 psi with the ACR working.

It probably either the valves are out adjustment or the ACR on the camshaft has failed. 793880 camshafts are bad for this to happen to them. Non invasive test consists of the checking the valve clearances and looking for the ACR bump on the intake valve as the engine approaches TDC compression stroke.

Now that sounds like something I have overlooked! Thank you KE4AVB. Seeing as I completely bypassed the solenoid, good ground, etc...and it still acted like a dead battery!
How do I check the ACR bump...what should I look for Sir?

[dart451]

Ok, I understand how the compression release works now...you know, this works sometimes...I need to check the valve clearance to see if it fixes the problem...I will do that tomorrow.

[bobodu]

I always suspect valve lash before replacing a starter...Something I learnt from Walt 15 years ago...
( I got to use "learnt" !!!)

[KE4AVB]

Also it is good to go ahead and do a leak down test while you got the valve off any 280000, 310000, or 330000 checking for a blow head gasket too. These series have a head gasket that tends to blow between the cylinder and push rod galley. While the valve is off during the test you can head it leaking in this area if blown in that spot. Normal blow-by sounds about the same at the dipstick as it does at the push rod galley but if the gasket is leaky it is louder at the push rod galley.

I know it is a little extra work but it will save you and the customer problems if you find it bad before the engine self destructs due to no oil. I just did this on one that was 1 qt low on oil that the only complaint was I hit a tree stump. Four hours beating the deck back to near level cut again and when I went through a normal inspection of the mower otherwise.