75 JD 800

Hansy · Post by **Hansy** » Sat Dec 20, 2008 1:16 pm

When i first got my sled about a month ago the engine was seized, i filled the cylinders with penetrating oil and let it set for a few days until it freed up. Now it will rotate but only half a turn so i used a borescope and looked in the cylinders and the left piston looks like it has two little square type things on the edge of the piston almost directly across from each other. Any ideas on what they might be and what i should do next?

big danno 1970 · Post by **big danno 1970** » Sat Dec 20, 2008 1:23 pm

sounds like a good candidate for a complete tear down. Inspect all parts carfully and replace as necessary including crank seals.

Hansy · Post by **Hansy** » Sat Dec 20, 2008 1:38 pm

yeah, that's what i thought. i was hoping i would be able to ride it this winter and then i would pull it apart in the spring and redo it. oh well there isn't much i can do about it

Hansy · Post by **Hansy** » Sat Dec 20, 2008 5:15 pm

i will try that but i don't think that's the problem cause i can rotate the engine one half turn which brings the piston from bottom to top but it won't go back the bottom unless i rotate it backwards.

JDT · Post by **JDT** » Sat Dec 20, 2008 9:03 pm

Only way to know for sure is spend some quality time with the engine and a few sockets.

Hansy · Post by **Hansy** » Sat Dec 20, 2008 9:30 pm

yeah, i will hopefully get a chance to do that this week cause it should be rather quiet at work seeing as it is four days till christmas

JDT · Post by **JDT** » Sun Dec 21, 2008 10:00 am

As that is a very nice condition machine you have and only built one year, I would not be affraid to put the money into it.

Hansy · Post by **Hansy** » Sun Dec 21, 2008 11:21 am

yeah, i was thinking of repainting and getting new decals for it. I don't know where i would be able to find the correct paint, the decals i'm not worried about cause my wife can make them for me seeing as she is a graphic designer.

Hansy · Post by **Hansy** » Thu Dec 25, 2008 1:58 pm

Well i pulled the heads off yesterday and found some crap on the left piston, so i cleaned it all off and put the head back on with a couple nuts and then slowly turned it over with the pull start, it rotated probably three or four times and then stopped so i pulled the head off again and there was nothing there so i pulled the other one off too and there was nothing there either. ant ideas what might be causing this? could it be a broken crank?

Post by **Matt** » Thu Dec 25, 2008 2:15 pm

Hansy,
Not to sound rude, but you need tear the engine apart to find the problem. There is no point to guessing at it. Merry Christmas

JDT · Post by **JDT** » Thu Dec 25, 2008 4:29 pm

Complete step-bystep instructions and pictures are in the Service Manual.
Very well written for any level of skill in engine teardown repair and rebuilding.
If you do not have one it is a great idea to lay your hands on one as it covers not only the engine but chassis, steering, electrical ect.

Post by **ICCSF 108** » Fri Dec 26, 2008 1:04 am

Hansy, I'll look into my Cristal Ball first part of next week & let you know what is the problem with it, In the mean time as JDT has said,

get a Service Manual for your sled, as you will need one to repair your engine..

Richard

400brian · Post by **400brian** » Fri Dec 26, 2008 1:19 am

The guys have this covered pretty well. Unless something is jamming up inside the recoil housing, or an ignition component out of place, you have something in the bottom of the crank case. It doesn't take much, I had a tiny washer in the bottom of a 340S case, and it kept the crank from turning 360 degrees.

JDT · Post by **JDT** » Fri Dec 26, 2008 11:25 am

Brian brought up a good point.

A broken recoil pawl was what I found once that kept a engine from doing a full 360.
I also found a dislogged magnet on the recoil twice.
However both of these problems offered only 90 degress of rotation.

On this one my orb of glass says broken skirt.

Hansy · Post by **Hansy** » Fri Dec 26, 2008 9:50 pm

ok, well i guess if it's not to busy at work next week i might get a chance to pull it apart and try and find the problem