Drive shaft snapped (1990 140hp)

[archcycle]

1990 140hp

I was running about 3k RPM last weekend when I heard a BANG clack clack clack then the motor smoothed out. I thought it sounded and felt a lot like what people describe clutch dogs shearing off as, but then I dropped the LU (after being towed home) and found this. Pulled off the water pump housing to begin trying to disassemble the LU but more than just the pump housing lifted when I pulled it up..



Putting it into gear by pushing and pulling the shift shaft Does engage both F and R and when in gear the prop spins that visible portion of the drive shaft freely so it's not like the gears locked up and and it twisted the drive shaft off.

I'm thinking maybe this had something to do with it:



This got to the present condition from looking great quite fast. The cover mount was completely corroded on the inside and it broke apart when I took it off.

Could it be that the mount was rotted and allowing the motor to bump around and created some stress fractures in the drive shaft that eventually snapped at this pressure point where it hits the metal casing on its way into the gearcase?

How did I snap this??

-----

I'm working from a factory service manual.

I have a v6 gearcase that used to be here that I'm going to see if I can cannibalize the driveshaft off of and a 1986 200hp that i'm going to see if I can cannibalize the mounts and mount covers off of. So far in the gearcase teardown I've got the water pump off and the prop shaft bearing housing's 4 bolts removed but can't find a big enough puller to get the housing pulled out yet. I picked up a puller with 8" arms at harbor freight today that i'm going to try when I get home.

Any tricks to getting that bearing housing out?

 

[airman1094]

Re: Drive shaft snapped (1990 140hp)

First off ouch! I think it could have occurred as a perfect storm...some excess lateral movement that caused stress fractures and maybe some corrosion inside the steel being a it is right below the water pump! Not to sure! As far as the bearing carrier, get yourself a 2 jaw puller( and a couple bolts if your carrier has the threaded holes ), WD 40, and some heat preferably a heat gun since its harder to ruin the metal! Spray some WD around the carrier where it meets the housing about 12 hrs prior to working on it! After the WD soaked drain the gear lube and remove the carrier bolts. Put pulling pressure on the carrier and apply heat to the outside of housing, not the carrier itself! Heat it till its hot to touch and wrench down on the puller! Should pop out!

 

[boobie]

Re: Drive shaft snapped (1990 140hp)

When you go to pull the prop shaft bearing carrier out, you may have to use some heat on the g/c in that area.

 

[archcycle]

Re: Drive shaft snapped (1990 140hp)

The puller from harbor freight isn't quite going to do it and I tried local auto stores and found nothing.

How about a flywheel puller with long threaded rods matching the carrier retention bolts (acquisition for tomorrow) and screw the rods a few threads into two of the deep end of the carrier but not into whatever it's bolted to and pull against the end of the prop shaft? Or is that exactly what you're saying airman1094?

 

[Solittle]

Re: Drive shaft snapped (1990 140hp)

The corrosion on the mid section in the photo is the result of electrolysis me thinks - it acted like the zincs. This would be from some sort of electrical leak - do you dock at a marina? Don't think this has any relationship to the driveshaft though.

 

[classiccat]

Re: Drive shaft snapped (1990 140hp)

The puller from harbor freight isn't quite going to do it and I tried local auto stores and found nothing.

How about a flywheel puller with long threaded rods matching the carrier retention bolts (acquisition for tomorrow) and screw the rods a few threads into two of the deep end of the carrier but not into whatever it's bolted to and pull against the end of the prop shaft? Or is that exactly what you're saying airman1094?

Those long grade-5 bolts probably came from the HF kit :lol: I put a nail in to stop the propshaft from spinning. And as boobie & airman said, give the housing some heat in the area of the forward-end of the bearing carrier.

 

[classiccat]

Re: Drive shaft snapped (1990 140hp)

that busted driveshaft is all kinds of crazy! :shocked:

 

[airman1094]

Re: Drive shaft snapped (1990 140hp)

Yeah the wheel puller kit from hf is not sufficient unless you get threaded rods long enough or you get a longer jaw puller like bluefin has? If your model engine has threads in the prop end of the carrier then you can use threaded rods or long bolts to pull it out...otherwise you'll have to use long jaw pullers (like the ones in Bluefin's pics above) but instead put the jaws under the back of the prop side of the carrier! Believe me it's a somewhat frustrating thing...I just did a seal and o ring job on the bearing carrier few days ago! I'll try to get you some photos that may help...

 

[airman1094]

Re: Drive shaft snapped (1990 140hp)

This one has threads for pulling on the front( left end of pictured carrier).....whereas one without those 2 threaded holes requires a pair of jaw pullers to pull from behind the prop end...the other 4 holes are not threaded for the bolts that attach to the retainer ring...which holds the carrier in place (right end of pictured carrier)

Sorry the pics aren't the greatest...got them from google image search..hope they help!

 

[archcycle]

Re: Drive shaft snapped (1990 140hp)

I somehow made it out of the house this morning without a carrier bolt. Does anyone know offhand what the bolt size/thread is?

 

[airman1094]

Re: Drive shaft snapped (1990 140hp)

5/16-18 I believe...you'll need them about 8 inches long...if its the same as mine for the puller...the four that attach it to the retaining ring are 1/4-28x1

 

[Chris1956]

Re: Drive shaft snapped (1990 140hp)

One of my co-workers had his driveshaft break on a 90HPV4. It was a trailored boat, which he flushed each use. I was real surprized it broke, as it should be one of the strongest parts, and he didn't even hit anything. I considered it to be defective.

 

[archcycle]

Re: Drive shaft snapped (1990 140hp)

5/16-18 I believe...you'll need them about 8 inches long...if its the same as mine for the puller...the four that attach it to the retaining ring are 1/4-28x1

I got threaded rods in these sizes and no luck, but today I have the bolts to try to match. If no luck there I could probably just take the rods and bolts down to a welding shop and have them weld the original bolts to the end of the rods (stopping by the marina on my way home to get 2 new bolts) and then I'd have two puller arms to thread a bit into the deep end of the bearing carrier. This doesn't seem like it should be so difficult.

 

[classiccat]

Re: Drive shaft snapped (1990 140hp)

I got threaded rods in these sizes and no luck, but today I have the bolts to try to match. If no luck there I could probably just take the rods and bolts down to a welding shop and have them weld the original bolts to the end of the rods (stopping by the marina on my way home to get 2 new bolts) and then I'd have two puller arms to thread a bit into the deep end of the bearing carrier. This doesn't seem like it should be so difficult.

a few mins ago I thought the inner holes of the bearing carrier are clearance holes then double checked your parts diagram and it's secured with a tab retainer.

 

[classiccat]

Re: Drive shaft snapped (1990 140hp)

looking at this a bit, not having those clearance holes, you could be working against a vacuum once the bearing carrier starts to move (pulling on a plunger)..at least until the B2B seal hits the taper in the prop shaft; I'd make sure the vent/drain screws are removed.

 

[V153]

Re: Drive shaft snapped (1990 140hp)

One of my co-workers had his driveshaft break on a 90HPV4. It was a trailored boat, which he flushed each use. I was real surprized it broke, as it should be one of the strongest parts, and he didn't even hit anything. I considered it to be defective.

Hmm. It wouldn't by any chance have been an '86? Feel his pain. I was cruising along at about 30-3500 when the driveshaft decided it'd had enough. Wasn't accelerating or decelerating hard, didn't hit anything. Just all of a sudden it sounded like it shifted into neutral?! Sheared off right above the water pump housing.

 

[airman1094]

Re: Drive shaft snapped (1990 140hp)

I got threaded rods in these sizes and no luck, but today I have the bolts to try to match. If no luck there I could probably just take the rods and bolts down to a welding shop and have them weld the original bolts to the end of the rods (stopping by the marina on my way home to get 2 new bolts) and then I'd have two puller arms to thread a bit into the deep end of the bearing carrier. This doesn't seem like it should be so difficult.

Sorry about that...ours have different threads...

 

[archcycle]

Re: Drive shaft snapped (1990 140hp)

Sorry about that...ours have different threads...

You were actually correct it was 1/4 x 28. It turns out the rods were 20.

I rigged this up and failed:


It bent the crap out of the rods and i started to get concerned about the amount of lateral force on the prop shaft as the rods bent and the puller torqued sideways so i let this one go. For all this trouble and time i'm starting to lean towards just finding another one on ebay.. fishing season is on after all.

 

[airman1094]

Re: Drive shaft snapped (1990 140hp)

Did you use heat? And did you empty the gearcase lube? Mine bent some rods until I heated the crap out of the outer case!

 

[boobie]

Re: Drive shaft snapped (1990 140hp)

If I read your picture right you're not supposed to be pulling on the retainer bolts as the retainer is held in by a snap ring. There are two holes in the prop shaft carrier which you should be pulling on. They are either 5/16" or 3/8 ". After you remove the carrier you can then remove the snap rings to get into the rest of the G/C.