Picked up a free Cub Cadet 383 Hydro!

[cdahl383]

Went for a walk yesterday with my wife and saw this old riding mower up near the road as we were walking. Figured it was for sale, but didn't see a For Sale sign on it. Got closer and saw someone had taped a FREE sign on it! Couldn't pass that up! Got it back home and figured I'd look it over the next day.

It was kind of dirty, but looked complete. Has a relatively new battery. Checked the oil and it does have oil in it. Tires seem to hold air and look decent. Mower deck looks complete. Cleaned it up so it wasn't so dirty and grimy. Charged up the battery and hooked it up. Engine turns over. Tested for spark and it has spark. Cleaned the air filter which was pretty nasty.

Did a compression test and only got 30psi. Hoping it's just a stuck or sticky valve.

I've never worked on one of these old Cub Cadets before, so I have a few questions:

1.) What would I need to do to check the valves (remove rocker cover?)
2.) If there's a stuck valve how would you free it up? Spray carb cleaner, Kroil, marvel mystery oil, etc?
3.) If it's not the valves causing low compression, it would have to be either the piston rings or maybe a leaking head gasket?

If I can figure out the compression issue then I'll move on to removing the carb and cleaning it, etc. Not going to bother with that until I know the engine is alright.

Hoping I can get this thing running. It would be cool to get it running for basically nothing!

 

[staninlowerAL]

Congrats, you have nothing to loose except some time and if you decide to abandon the effort you can part it out or sell for scrap. Either way you are a winner. JMHO Stan

 

[Jim Becker]

Is that one of the engines with a compression release that you have to crank backwards to do a compression test? Just asking, I have no idea.

 

[cdahl383]

Is that one of the engines with a compression release that you have to crank backwards to do a compression test? Just asking, I have no idea.

I have no clue. I wonder where the compression release is if it had one? I’ll see if I can find some info.

 

[cdahl383]

Congrats, you have nothing to loose except some time and if you decide to abandon the effort you can part it out or sell for scrap. Either way you are a winner. JMHO Stan

That’s what I figured. Not much to lose. Something to tinker with.

 

[cdahl383]

Is that one of the engines with a compression release that you have to crank backwards to do a compression test? Just asking, I have no idea.

I looked up the parts diagram for the engine and that part number for the cam does not show a decompression lever on the cam. I don’t think it has it.

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/briggs-stratton-engine/200000-399999-series/252700-to-252799/252707-0228-99/piston-grp-crankshaft-cam

 

[T-Mo]

The 383 and it's predecessor, the 382, were very good lawn tractors. Cub Cadet made some good ones in the late 70s (though they would be red) and most of the 80s. It was in the mid to late 90s, MTD started to cut the quality on the CCs.

Being a vertical shaft engine, one from Harbor Freight might be your best bet to revive this machine.

 

[cdahl383]

Found the reason why the engine was low on compression. Blown head gasket. Blew out by the exhaust valve.

Cylinder looks good to me. Valves look okay too.

Going to clean things up, order a new gasket, and clean the carb while I’m waiting for the gasket. Hopefully it’ll run after that!

 

[dgrapes59]

That's a fairly common problem with the older Cadets, many people just give up on them. Be sure to check the head to make sure it's true, slight warpage will cause another gasket failure. They're easy to true with some fine wet sandpaper, a flat surface like a piece of glass and a little effort.
That model is more of a riding mower than a garden tractor. So not really designed for serious ground engagement but should make a great mower, especially for the price!

Best of luck,

David

 

[cdahl383]

That's a fairly common problem with the older Cadets, many people just give up on them. Be sure to check the head to make sure it's true, slight warpage will cause another gasket failure. They're easy to true with some fine wet sandpaper, a flat surface like a piece of glass and a little effort.
That model is more of a riding mower than a garden tractor. So not really designed for serious ground engagement but should make a great mower, especially for the price!

Best of luck,

David

Yeah I think this guy just gave up. No way you’d know it had a blown head gasket unless you did a compression test and pulled the head.

The head seems okay from what I can see. I put a straight edge on the mating surface and it laid flat. It was pivoting on any high points or anything.

What grit sandpaper would you use to clean up the mating surface? 600 grit? 1000 grit? I wouldn’t think you’d want to go too rough and cause grooves.

 

[dgrapes59]

The original write up I followed starts with 180 then finishes with 220, but it needs to be wet/dry paper, used wet. I've done several as this is a common problem. I made a jig to clamp the paper down. The glass needs to be modern tempered so it's flat. I used what I had but it was a little smaller than ideal, it worked, but a piece bigger than the paper would be better.
A quick Google search showed the process, he used 320, took longer for the same results. Here's the video:

Good luck,

David

 

[dgrapes59]

Also, like with any head, be sure to chase the threads in the block and torque in sequence, in steps to manufactures specs. Run for 20-30 minutes and then retorque when it cools.

With any luck you'll be mowing soon!

 

[CharlieK]

thanks for that, David

 

[cdahl383]

The original write up I followed starts with 180 then finishes with 220, but it needs to be wet/dry paper, used wet. I've done several as this is a common problem. I made a jig to clamp the paper down. The glass needs to be modern tempered so it's flat. I used what I had but it was a little smaller than ideal, it worked, but a piece bigger than the paper would be better.
A quick Google search showed the process, he used 320, took longer for the same results. Here's the video:

Good luck,

David

Cool! That makes sense.

I don’t have any glass to use. What about a granite countertop? Big flat level etc. could tape the sandpaper to that and use that?

 

[Jim Becker]

Granite countertop is an excellent choice. I have a hunk of Silestone (quartz) that was left over after a kitchen sink was installed.

 

[cdahl383]

Granite countertop is an excellent choice. I have a hunk of Silestone (quartz) that was left over after a kitchen sink was installed.

Cool, maybe I'll give that a try then. I don't have any leftover granite, I'll just tape some sandpaper to our granite countertop in our kitchen and see if that'll work. I'll probably do that when my wife isn't home too.

 

[dgrapes59]

maybe I'll give that a try then. I don't have any leftover granite, I'll just tape some sandpaper to our granite countertop in our kitchen and see if that'll work. I'll probably do that when my wife isn't home too.
Not sure I'll endorse that LOL! A 10X12 piece of glass is available at most home improvement stores for under $5, might be worth the investment to keep peace in the family

 

[staninlowerAL]

maybe I'll give that a try then. I don't have any leftover granite, I'll just tape some sandpaper to our granite countertop in our kitchen and see if that'll work. I'll probably do that when my wife isn't home too.
Not sure I'll endorse that LOL! A 10X12 piece of glass is available at most home improvement stores for under $5, might be worth the investment to keep peace in the family

A very wise investment! The returns on it will last a lifetime....... JMHO Stan

 

[Jim Becker]

A 10X12 piece of glass is available at most home improvement stores for under $5, might be worth the investment to keep peace in the family

I have a piece of double pane glass, cracked on one side. It was here when I moved in. If I didn't have the quartz scrap, I would probably have used it. I imagine pieces of glass like that can be found for free by taking a Dumpster dive behind about any glass shop.

 

[cdahl383]

maybe I'll give that a try then. I don't have any leftover granite, I'll just tape some sandpaper to our granite countertop in our kitchen and see if that'll work. I'll probably do that when my wife isn't home too.
Not sure I'll endorse that LOL! A 10X12 piece of glass is available at most home improvement stores for under $5, might be worth the investment to keep peace in the family

Haha! Yeah that's probably a better idea!

I'll swing by Lowe's later today.

One thing I noticed is the head has a lip on the backside on part of it. I guess that could be sanded down too along with the mating surface though too without causing any problems.