742b engine locking up

[rustywalrus41]

I have a 742b with the Mitsubishi engine. Waiting to receive manual but in the meantime wanted to ask the forum for help. Engine spins about 180 degrees before a loud clunk is heard and it locks up. Is there access for the couple by lifting the cab or does engine need to be pulled

 

[laurencen]

do you have a borescope you can feed it at the back of motor to look at the coupler and see if the fan is turning?

 

[rustywalrus41]

I'll give that a try thank you

 

[Dave J]

There are only 2 nuts in the cab that need to be removed to tip it. They should be 3/4", then you can see the coupler and watch how it moves. If you have not greased it recently it would be a good time to do it especially the slide on the spline.

 

[reaperman]

The U-joint between the engine and hydro pump may be broken. You dont want the machine to start without knowing for sure if it's the U-joint or not. If it does happen to start with a bad U-joint, bad things can happen fast.

 

[rustywalrus41]

The U-joint between the engine and hydro pump may be broken. You dont want the machine to start without knowing for sure if it's the U-joint or not. If it does happen to start with a bad U-joint, bad things can happen fast.

Thank you sir waiting for towing company to bring the unit to my house to begin looking at it. Gonna try to sneak in the camera and take a look

 

[oiu789]

Could be in the engine. IE a broken rod.

 

[reaperman]

If the u-joint isnt broken, grease it while you're already dirty. Its not easy, but its often forgotten since its such a pain to access

 

[oiu789]

Could be in the engine. IE a broken rod, a dropped valve or something else in the engine. What makes you think it is the coupler?

 

[reaperman]

A broken coupler is just a suggestion. Given the age of the machine and being its not easy to maintain, plus many owners arent aware the u-joint is even there.

 

[rustywalrus41]

A broken coupler is just a suggestion. Given the age of the machine and being its not easy to maintain, plus many owners arent aware the u-joint is even there.

Coupler looks fine removed plugs and with the scope I can see the problem is in #1 cyl. I will make time this week in the afternoons to start pulling the engine. After scraping all the grease and dirt looks like its just the 1/2 nuts holding the plate and just moving hoses and wires out of the way.

 

[laurencen]

what did you find with #1 cylinder

 

[rustywalrus41]

what did you find with #1 cylinder

Other 3 cylinders move #1 is not moving at all.

 

[laurencen]

bummer,