Shaft drive transmission failure - diagnosis

Momac

Momac

Well-Known Member
Joined
7 Feb 2008
Messages
7,626
Location
UK
Visit site
I have recently been traveling in company with a shaft drive boat. It’s twin engined with kamd43’s.
There has been a transmission failure on one engine which is thought at this stage to be the drive plate failure. The gearbox oil is clean. I understand the shaft turns slowly if engaged in gear but the engine revs freely with no increase in shaft revolutions.
Any thoughts?
 
kashurst said:
Is there drive in reverse?
If not probably the drive plate, if access is good easy to fix
Click to expand...

I presume he has tried reverse but will check.

It was a sudden failure with no prior warning.

Apparently the engine has to be released from its mountings and jacked up prior to removing the bell housing ?
Access above the starboard engine and gearbox is not great due to fitted saloon seating (Sealine F36 - flybridge boat)
 
I doubt he needs to jack up engine as I think engine mounts are on the engine not the gearbox. Still if space is limited patience and swearing should do it.
 
MartynG said:
I have recently been traveling in company with a shaft drive boat. It’s twin engined with kamd43’s.
There has been a transmission failure on one engine which is thought at this stage to be the drive plate failure. The gearbox oil is clean. I understand the shaft turns slowly if engaged in gear but the engine revs freely with no increase in shaft revolutions.
Any thoughts?
Click to expand...

Check the shift cable moves the selector .

Check the filter top cover is tight and the o ring is good , if it’s loose the oil pump will suck air giving no clutch pack pressure .

If you can remove the oil pump housing it’s 6 Allen cap bolts it pulls off with a gentle wiggle after the cooler hoses have been disconnected .
What you see then is the end of the shaft that goes through the box into the flywheel drive plate , start the engine if it turns the drive plate is ok, you can also try and turn it in either direction with the engine off , it if spins it’s the driveplate that’s broken away from the flywheel.
 
volvopaul said:
Check the shift cable moves the selector .

Check the filter top cover is tight and the o ring is good , if it’s loose the oil pump will suck air giving no clutch pack pressure .

If you can remove the oil pump housing it’s 6 Allen cap bolts it pulls off with a gentle wiggle after the cooler hoses have been disconnected .
What you see then is the end of the shaft that goes through the box into the flywheel drive plate , start the engine if it turns the drive plate is ok, you can also try and turn it in either direction with the engine off , it if spins it’s the driveplate that’s broken away from the flywheel.
Click to expand...

Paul, I know you do this a lot but really this is an awesome reply, great pointers and practical advice. Top man.
 
jimmy_the_builder said:
Paul, I know you do this a lot but really this is an awesome reply, great pointers and practical advice. Top man.
Click to expand...
Positively +1.
While reading his instructions, I almost felt capable to do the job myself, even without having ever dealt with that engine. :encouragement:
 
jimmy_the_builder said:
Paul, I know you do this a lot but really this is an awesome reply, great pointers and practical advice. Top man.
Click to expand...

Cheers Jimmy , I always like to try and help , martyn G has been a client in past years , he is only trying to help his Farndon boating friends I’m sure , I am local to there boats so you never know work might come my way .
 
If its a HS 63 couple around s/hand at the moment.
Club member recently had one fail in a Princess 41 with a pair of 375 HP Volvos.
It was 50% cheaper to buy a replacement unit than get his old one rebuilt by the folks at Queenborough.
Also a lot quicker to get boat moving again.All able to be done afloat.
Fortunately had standard stern glands, able to slide shafts back after undoing flexi coupling bolts.
 
Last edited:
oldgit said:
If its a HS 63 couple around s/hand at the moment.
Club member recently had one fail in a Princess 41 with a pair of 375 HP Volvos.
It was 50% cheaper to buy a replacement unit than get his old one rebuilt by the folks at Queenborough.
Also a lot quicker to get boat moving again.All able to be done afloat.
Fortunately had standard stern glands, able to slide shafts back after undoing flexi coupling bolts.
Click to expand...

These shaft drive boats are nothing but trouble. ?
I will stick to my outdrives.?
 
You must log in or register to reply here.

Share this page

Top