76 300

jereeich · Post by **jereeich** » Fri Jan 26, 2007 12:12 pm

I picked up a 76 300 in good condition for $20. Problem is it hasnt ran in a few years and the motor is locked up tight. Guy sad it ran good when parked a few years back. What should I do to get it loosened up? Is there ging to be anything wrong with the crank or the bearings if/when I get it freed up? Please help.

Thanks

bpmailman · Post by **bpmailman** » Fri Jan 26, 2007 1:23 pm

I use a mixture of diesel fuel and dex III. Pour it in the spark plug holes and let it set a couple days. Then grab the clutch and slowly rock back and forth. If it hasn't sat full of water in a pasture this usually works great for me.
mike

400brian · Post by **400brian** » Fri Jan 26, 2007 4:50 pm

After you have it loosened up, it would probably be best to pull the jugs off and make sure the rings are free, and in general clean things up.

If the crank has any indication it has corroded, it would be best to rebuild or replace, along with the seals. Depends alot on storage conditions, and what had it stuck.
Also depends on your goals and how much time and $$ you want to stick into it.

If you just un-stick and run it, who knows how long it will last.

grasscutter97 · Post by **grasscutter97** » Fri Jan 26, 2007 11:27 pm

I personally use PB Blaster penetrating spray. After you get the pistons unstuck, then run oil down cylinders to get them lubed up.

Clean out fuel system, lines, filter, carb. Check compression, spark.

See if it runs.

Rodimus Prime · Post by **Rodimus Prime** » Sun Jan 28, 2007 4:25 am

im waiting on this one if its what i think it is yourlube ideas wont do a thing.

grasscutter97 · Post by **grasscutter97** » Sun Jan 28, 2007 12:07 pm

Rodimus...not sure if you are talking about the product I use or not, but PB blaster is not your usual 'penetrating spray'.

It is NOT WD-40 which most people incorrectly use for stuck bolts but in actuality is NOT a penetrant at all, (WD stands for 'W'ater 'D'eterrent, and originally was made for use in dispersing water from electrical parts). PB is sold in spray cans like the liquid wrench, but it is also sold in gallon cans (like you buy for carb dipping), so that you can immerse small parts for a complete soak. Higher priced product, but works flawlessly.

It has broken so much stuff loose I've lost count. Here are 2 things I used it on that other products didn't work:

1-Had 2 bogie shafts from a 71 Yamaha GP that were froze solid. No movement anywhere. Poured the PB in a shallow metal pan and soaked it overnight. All parts of the shaft came apart with minimal effort the next day.

2-Used it on an engine years ago, that a guy had tried unsuccessfully for quite some time using different oils, fuels, etc. We poured in the PB and had it unstuck in less than 20 minutes. (Maybe all the stuff he tried beforehand actually did start to loosen it.) Kind of like the kid who can't get the lid off the pickle jar, so his sister grabs it and snaps it open with zero effort!, and he says "ya, but I loosened it for you..."

Try it on your next stuck engine project, you'll be pleased with the results.

400brian · Post by **400brian** » Sun Jan 28, 2007 5:22 pm

As I said previously, and I suspect Rodimus is thinking as well, it may depend on why it is stuck. If it is seriously seized, not stuck due to corrosion, lubricants may not help alot.

grasscutter97 · Post by **grasscutter97** » Sun Jan 28, 2007 10:00 pm

Agreed. 'Seized' and 'stuck from sitting' are 2 totally different things.

JDFanPa · Post by **JDFanPa** » Sun Jan 28, 2007 11:07 pm

the big issue on a tuck motor is it stuck in the cylinders or the crankcase most times if its just in the cylinders you can move the clutch a very very and I mean vey small amount barely noticable. If the cylinders are rusted you have to work it back and forth. I use a wrench on the clutch bolt and a socket on the flywheel nut so you can work both directions without loosening a nut/bolt. Worse case if its got alot of junk in the cylinders and you get it free it will have stuck rings nyway.

jereeich · Post by **jereeich** » Wed Jan 31, 2007 11:58 am

Thanks guys. I got it fired up the other night, cleaned the tank, replaced fuel filter and lines, just waiting for the carb rebuild kit now. The crank however does sound a little dry. Is there something I can do to help this other than rebuilding the crank?

JDFanPa · Post by **JDFanPa** » Thu Feb 01, 2007 12:42 am

I would just run it maybe a lil heavy on the oil mix hopefully it will clear up or at the very least last awhile before failing. These motors arent that hard to find if you end up neding 1. Ive got 2 sleds running this motor and 2 spare motors on the shelf. For the cost of a crank rebuild you can easily buy a motor or a parts sled. Id guess it really depends on your longterm plans for the sled and how much and far you will ride it.

grasscutter97 · Post by **grasscutter97** » Thu Feb 01, 2007 6:08 pm

I agree. Its very easy to find a complete running motor to swap out.

If you are dead set (as I was, when doing a 300 restore) to keep the original engine in it, you can find NOS cranks for that engine, for under $50!