Motor runs, no forward or reverse, Prop doesn't spin

[El Captain]

I have a 1991 bayliner 20' boat, with a 4.3 Mercruiser I/O Alpha one. At the lake it was running fine until i took off and all that happened was the engine sped up and made a whinning noise.After that the boat would not even engage into gear. <br />Looking down into the back of the engine compartment there are a bunch of metal shavings. Any ideas of what is wrong? and how/ what to fix?

 

[Haut Medoc]

Re: Motor runs, no forward or reverse, Prop doesn't spin

Welcome to iboats... Either you have spun the hub on your prop,(hopefully) or your engine coupler has stripped,(bad). Did it over heat? JK

 

[Haut Medoc]

Re: Motor runs, no forward or reverse, Prop doesn't spin

Oops! How new/old is your shift cable? Does the prop turn at all? The metal shavings suggest coupler. What you should do is pull the drive and inspect the splines on the drive shaft, if they are chewed up, then your coupler has most likely gone south from engine mis-alignment. Test the drive manually while it's out. Put the shift lever in foreward, and turn prop ccw. If it engages it means your drive is ok. Turn the shaft to the side andturn prop cw it should engage. I'm sure there will be other members who can point you to some helpful links...JK

 

[El Captain]

Re: Motor runs, no forward or reverse, Prop doesn't spin

The shift cable is probable the original one. and no the prop doesn't move at all. Why would there be metal shavings and what causes the mis- alignment?

 

[KRS]

Re: Motor runs, no forward or reverse, Prop doesn't spin

El Captain... listen to me and kopec... this same thing happened to me. EXACT same thing.<br /><br />I stripped the threads in my coupler, that means the drive comes off, the engine comes out, a new coupler is installed on the flywheel, engine goes back in (if mounts are solid), engine is aligned, drive is installed (after it's serviced because it's a good time to). Also a good time to replace the bellows, etc.<br /><br />DON'T RUN IT BECAUSE without the drive input shaft spinning, the water isn't making it to the engine. That is why he asked if it overheated.

 

[KRS]

Re: Motor runs, no forward or reverse, Prop doesn't spin

The misalignment is caused by different things, mine was caused by the motor mounts (into the wooden stringers in the floor) were rotted out and when I applied throttle, the engine was torque rolling out of alignment and pretty soon I heard a strange spinning whining noise

 

[El Captain]

Re: Motor runs, no forward or reverse, Prop doesn't spin

wow thanks for all the help. Is all of this something that im able to do? and where can i find parts?

 

[El Captain]

Re: Motor runs, no forward or reverse, Prop doesn't spin

How do i align the engine?

 

[Don S]

Re: Motor runs, no forward or reverse, Prop doesn't spin

Without a service manual, I would say you have a zero percent chance of doing the job correctly so you don't have to do it 2 or 3 times and replace the things you broke.<br /><br />Below is a link to the only manual that will give you the help you need. The OEM manual.<br /><br /> Service Manual #7

 

[jmatteo1]

Re: Motor runs, no forward or reverse, Prop doesn't spin

Genuine Mercruiser Manuals, Iboats forum, time, patience, some mechanical ability, and CASH! It's very rewarding if you do it yourself. I had a spun coupler. There are a few photos on my project page at shareaproject.com Best of Luck,<br /><br />Joe

 

[KRS]

Re: Motor runs, no forward or reverse, Prop doesn't spin

I paid a mechanic to do mine, with rotton mounts, a new upper unit rebuild, and some other work it was $3,200.

 

[jmatteo1]

Re: Motor runs, no forward or reverse, Prop doesn't spin

I couldn't spend that much. Thats why I did it myself. That & the satisfaction of learing and doing it for myself. I only paid $750.00 for boat & trailer, so it would be hard for me to justify spending $3,200.00 to fix it to the "Boss"!!