Mercruiser lower unit will not spinn prop completely

[cbrooksfam4]

I have a 1989 Searay Seville cuddy cabin 21f with a 4cyclinder mercruiser moter in it handed down from father in law. He had the engine redone an foot rebiult around 1500 dollars worth of work. well he moved to maryland an left the boat to us. I was out on the water one day boat running great. Went to put on trailer an pushed throttle foward an nothing happened , current kept pulling out put in reverves nothing rpms go up but no movement. Thank god for long rope!!! anyway before all of this happen it was usaully had to get into neutral had to play an try to find the sweet spot to pop into neutral an when you put it into gear you would hear a little grinding noise an had to push the throttle an lot furhter than you had to in my other boat( which had a O/B in it...... ) to get a response from the engine..... I am a good mechanic if I know what to do but I rather hopefully get some help from here so I know where to start looking. Prop is ok not stripped out or anyhting I removed prop What Else Can I do??????:/

 

[Haut Medoc]

Re: Mercruiser lower unit will not spinn prop completely

Sounds like you need a lower shift cable.....
Here ia a link to the service manual.....
Sounds like you need to perform some preventative maintenence as well.......
That is in here , too.......
http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf
Good Luck........

PS.....
You should inspect the condition of the u joint bellows at this time, it & the shift cable have approximately the same life expectancy.....
If the rubber is suspect, replace it....
It is the only thing that keeps water out of your drive....
If it fails, you will be paying for a new drive......:%

 

[Limited-Time]

Re: Mercruiser lower unit will not spinn prop completely

....."anyway before all of this happen it was usaully had to get into neutral had to play an try to find the sweet spot to pop into neutral an when you put it into gear you would hear a little grinding noise"..................

Never a good sign:'( Sounds as if it could be the lower unit. That would be where I started,........................ back up one step. If your going the DIY route get the correct Merc manuals before you go any further. It could also be a spun coupler, but thats to be determined. Good luck, and welcome to the boards.

Dang it Haut, you must type faster than me......

 

[cbrooksfam4]

Re: Mercruiser lower unit will not spinn prop completely

Well i went home Test Prop Not Prop Checked Cables Seem Fine but Maybe not??? Yet to Be determined. I started motor For first time this Year after all my Preps carbs, filters, oils, Lubes ect... Well I vaccumed out the whole engine compartment wiped down all nice an white stated the motor a few turns of a key it started squealed a minute then stop (belts) (Time to replace). Anyway Put in to Gear no Grind noise at all just motor reving up. Looked At prop. not Spinning, little more throttle it started to spin a little the more gas I gave it the more it went to barely spinning a so I looked a tthe back of The engine where the bell housing is located to see if the shaft there is spinning at the same rate as the motor or prop well it was the same rate as the prop (hardly at all) I noticed some nice new metal shavings right below the shaft so cut boat off disconnected everything. inspected closely an found that right where the shaft goes into the engine is where the shavings seem to be coming from. No rubber buring smell no smoke, once the squealing stopped it was just quite motor noise an exhaust so what would be my next step guys an i ordered the man.. mercruiser by seloc here from iboats an also did the online book also...... I am Ready for Instructions......

 

[Bondo]

Re: Mercruiser lower unit will not spinn prop completely

so what would be my next step guys

Your Engine Coupler is Shot,.......

Pull the Drive,.....
Pull the Engine,.....
replace the Coupler,......
Reinstall everything,+ Realign it......

 

[bjcsc]

Re: Mercruiser lower unit will not spinn prop completely

Yep...those shavings used to be splines...

 

[cbrooksfam4]

Re: Mercruiser lower unit will not spinn prop completely

I do not have to pul the motor out I don't think i have a about 15 to 18 inches of room once I pull the drive shaft out. Or is the another reason why I should pull the motor besides room to work???? Do you think i will need a new drive shaft also an where is a good place to get a new coupler from here online I am On a budget But not wanting to have to repace this every year also

PS..... Thank you for the Help guys......

 

[Don S]

Re: Mercruiser lower unit will not spinn prop completely

Sounds to me like you have one of those few with a jackshaft in it.
After you remove the drive shaft, you still have to remove the flywheel housing to get to the coupler. Which means you must remove the housing with the rear motor mounts for the engine. If you can raise the back of the engine to do that, then you won't have to remove the engine. BUT!!! You MUST get the engine aligned properly when you put it all back together or you will loose couplers constantly.
You really need to get Merc service manual #10 for your engine. It has all the details.

When you pull the shaft out of the coupler, check the splines if they are worn down to a point or close to it, you will need a new shaft. Compare the splines that go into the coupler with the part that doesn't fit into the coupler (usually about an inch)

 

[Bondo]

Re: Mercruiser lower unit will not spinn prop completely

Ayuh,..........

With only 2 little things,...... Those parts will Last almost Forever,.......

1) Proper Alignment.......

2) Regular Greasing..........

 

[cbrooksfam4]

Re: Mercruiser lower unit will not spinn prop completely

Nope not a jackshaft i just have alot of room back there i an redoing the rear seating an carpet an wiring for radio an cleaning up all the wiring removing old wires not used wiring for power converter i just lubed all greese points I could find changed oil wires plugs ect now i have to pull the out drive an pull the drive shaft an engine coupler hey I guess I have a lilttle bit of work ahead of me It really doesn't seem that difficult.

 

[cbrooksfam4]

Re: Mercruiser lower unit will not spinn prop completely

i would really like to order the part now but i am not sure which cuopler it is I think the part # is 18-2171 for a 1989 mercruiser 140 I am at work an do not have engine # but from what i can figure out i think it is right what do you guys think

 

[cbrooksfam4]

Re: Mercruiser lower unit will not spinn prop completely

THANKS GUYSo
ORDERED THE PART 18-21718) 8)
INSTALLING IT ON TUES OF NEXT WEEK AN I WILL BE PULLING THE MOTOR. IT WOULD BE ALOT EASIER FOR ME TO DO SO. AN THROW SOME PAINT DOWN IN THE HULL AGAIN TO JUST FREHEN-UP THINGS A BIT
THANK YOU AGAIN FOR ALL THE HELP

 

[Aquaman]

Re: Mercruiser lower unit will not spinn prop completely

hey I guess I have a lilttle bit of work ahead of me It really doesn't seem that difficult.

A good attitude makes any job easier