1989 Johnson Looper Drive Shaft Stripped

[scdeerslayer]

Hi, I have a 1989 Johnson Looper 225. The drive shaft stripped the last time I was out and looking for advice. I went to the marina and a new shaft was around $600 but he wanted to sell me a new lower unit with the shaft for $350 new seals and pressure tested. My question is (I couldn't get a clear answer at the marina) if I buy a new lower unit or just the shaft shouldn't I have to replace the coupler at the engine that the shaft goes into. I'm not a mechanic but it seems to me that if the shaft stripped the coupler had to also. He was telling me I simply had to install the lower unit and be on my way but I'm thinking this will simply strip the new shaft. If anyone can help out on this it will be greatly appreciated. Thanks.

 

[Chinewalker]

Re: 1989 Johnson Looper Drive Shaft Stripped

Depends on why the shaft spun out. The crankshaft splines are typically "harder" metal than the driveshaft splines, BUT the crankshaft splines are also prone to rusting if not properly serviced. If the spun splines were due to slam shifting, wake jumping, etc., then the new shaft may fix the issue. If the spun splines were due to rusted crankshaft, then they may have loosened their grip enough to allow the driveshaft splines to spin out. A new driveshaft may not last long in either case... Only way to know for sure is to check the crankshaft splines for wear...

 

[boobie]

Re: 1989 Johnson Looper Drive Shaft Stripped

Agree + 1 !!

 

[trendsetter240]

Re: 1989 Johnson Looper Drive Shaft Stripped

x3 agree with what they said.

I'd add that if you are paying a mechanic to check the crank splines it will get costly. The powerhead needs to be removed for this. And, if he does find that the splines are worn you are in for a whole heap of expense to repair/replace the crankshaft.

So keeping the potential cost in mind you could roll the dice with a new lower unit and keep using this motor for years to come. Or you could go down the path which may end up in a repair bill that's more than the cost of replacing the motor with another used one.

 

[scdeerslayer]

Re: 1989 Johnson Looper Drive Shaft Stripped

Thanks guys. I haven't had the boat very long and haven't dogged it hardly any. Before it spun completly it was like a transmission slipping at WOT every now and then. It would go into gear with out slipping perfectly fine. It completely spun when I was taking off from a stand still before the boat got onto plane it was the second time I had it out since I bought it. I knew it had to be something with the shaft because the water pump wasn't working while the engine was running. I thought the shaft had broken and now I wish it had and that was the only problem. All I did was the minimal and do a compreesion test which was perfect and took a chance on it. Thanks again for the help guys.

 

[boobie]

Re: 1989 Johnson Looper Drive Shaft Stripped

A good mechanic would have the correct light or scope to check out the splines from the bottom up. I can't see where if the d/s splines are bad the c/s is okay.

 

[scdeerslayer]

Re: 1989 Johnson Looper Drive Shaft Stripped

Thanks for the info I didn't realize the drive shaft went to the crank shaft I figured it went to a coupler and I could simply replace the parts. I talked to a buddy of mine that is a diesel mechanic and has a scope to check the c/s splines for me (thanks Boobie). This web site is awesome along with the people on here willing to help someone who has a question.