'88 XR4 150hp stops turning over, crank locks up

[pwrcrzy]

Just bought a Winner bass boat with a 88 XR4 on it. Installed a new battery, has not been run in over a year. I first removed the plugs, oiled it down. Not worried about the fuel system now, but when cranking it over, may crank over three of four revolutions then stop dead in its track. I have removed the flywheel cover, the crank is locked up not solid like a car block, but more 'rubbery' feeling when I try to turn the flywheel against the stop. I have not tryed to force it. I can rotate the flywheel backwards half a turn and it will crank over anywhere from two to four revolutions before locking up again. sometimes craking much longer than that. I then went ahead and sprayed a fuel mixture into the carbs and it did fire, pop through the exhaust a few times and stop abruptly. Again it cranks and locks. I do not want to do much more damage to it. I was able to get a compression reading of around 125 throughout all cylinders. I am a mechanic, just not an outboard mechanic, could something on the drive unit be failing? Maybe a rod getting ready to let go? The PO said that it ran good. Maybe i am missing something. With a good compression test, it proves the rod is still on the crank at least. The prop turns freely when in N and drives engine in drive. Any way of un-hooking it to verify it's in the engine? Also, how hard is it to split the case to verify the crank and components? Anything I need to know before it all jumps out??

Thanks in advance for all on your help.

David

 

[j_martin]

Re: '88 XR4 150hp stops turning over, crank locks up

Just bought a Winner bass boat with a 88 XR4 on it. Installed a new battery, has not been run in over a year. I first removed the plugs, oiled it down. Not worried about the fuel system now, but when cranking it over, may crank over three of four revolutions then stop dead in its track. I have removed the flywheel cover, the crank is locked up not solid like a car block, but more 'rubbery' feeling when I try to turn the flywheel against the stop. I have not tryed to force it. I can rotate the flywheel backwards half a turn and it will crank over anywhere from two to four revolutions before locking up again. sometimes craking much longer than that. I then went ahead and sprayed a fuel mixture into the carbs and it did fire, pop through the exhaust a few times and stop abruptly. Again it cranks and locks. I do not want to do much more damage to it. I was able to get a compression reading of around 125 throughout all cylinders. I am a mechanic, just not an outboard mechanic, could something on the drive unit be failing? Maybe a rod getting ready to let go? The PO said that it ran good. Maybe i am missing something. With a good compression test, it proves the rod is still on the crank at least. The prop turns freely when in N and drives engine in drive. Any way of un-hooking it to verify it's in the engine? Also, how hard is it to split the case to verify the crank and components? Anything I need to know before it all jumps out??

Thanks in advance for all on your help.

David

I'd pull the LU and see what it does with it off. If you want to run it, just rig a hose to the water tube hanging down.

hope it helps
John

 

[pwrcrzy]

Re: '88 XR4 150hp stops turning over, crank locks up

John,

Thanks
Is it just a matter of unbolting the lower unit, need to be in drive or neutral? I've seen it but never removed one before.

 

[sschefer]

Re: '88 XR4 150hp stops turning over, crank locks up

I wonder if it broke a reed and now it's going throgh the engine. You'd need to pull the intake off to find out. You might be able to see pieces of it through the plug hole but I doubt it.

If Johns suggestion of pulling the L/U doesn't stop the locking then that's what I'd do next.

 

[pwrcrzy]

Re: '88 XR4 150hp stops turning over, crank locks up

OK, just pulled the lower unit off and the input shaft is frozen, will not move but prop turns. Should I try to pull it apart? What is the best step from here to see if it is salvagleable?

thanks again

 

[sschefer]

Re: '88 XR4 150hp stops turning over, crank locks up

OK, just pulled the lower unit off and the input shaft is frozen, will not move but prop turns. Should I try to pull it apart? What is the best step from here to see if it is salvagleable?

thanks again

First off - Good call John!!!

Salvageable, maybe. Cost effective, probably not. Look for a decent recon here on iBoats in parts. You'll at least get a warranty. Might even get a discount if they let you use your L/U as a core.

You could spend the cost of a hours shop time to have it torn down and checked out. I'd tell you to tear it down and fix it yourself but the shop manual is about the same as the cost of an hours shop time and you can damage it further without the proper tools.

 

[j_martin]

Re: '88 XR4 150hp stops turning over, crank locks up

Scheffer, the clue for me was the "springiness" in the lockup. Says to me it's down the power train a ways.

Anyway, is it the original LU. It was a small bore prop, 1.78:1 originally. They are a little faster than a full sized LU, but if not kept in perfect tune and unabused, they fail frequently. Any V6 LU with the right length input shaft will bolt up.

 

[Faztbullet]

Re: '88 XR4 150hp stops turning over, crank locks up

To my knowledge nobody offers a exact reman unit for the small 1.78 ratio gearcase and it is known for pinion bearing failure as Jmartin said. Your best option is to install standard 2.1 ratio gearcase and change prop.

 

[nosgsxr]

Re: '88 XR4 150hp stops turning over, crank locks up

OK, just pulled the lower unit off and the input shaft is frozen, will not move but prop turns. Should I try to pull it apart? What is the best step from here to see if it is salvagleable?

thanks again

hey im about to part out a 92 merc 150 with a good lower unit and brand new water pump.. might even have a prop depending on what you need o yea its a 20inch shaft...send me a pm if u need anything