lost forward and reverse on mercruiser stern drive

[james_dorion]

hi again everyone; Mercruiser 165hp model number 21653 serial number 3465185. i think its a prealpha drive? I got towed in the other day. I had the boat running very well for the morning fishing with no problems. Then when on return home and engaging the trottle into forward position the drive made a grinding sound but still was somewhat in forward gear. I changed to reverse thinking seaweed (although i knew there wasnt any) then back to forward with the same outcome. I checked the linkages and all seemed well. Upon wiggling the shift cale and other parts of linkage, the gear makes no attempt for forward now and no grinding. When i jumped in the water to turn the propeller counter clockwise while the throttle was in forward gear. The propeller did turn with resistance and clicked in the counter clock wise rotation. The reverse also turned both directions with little force clockwise and a clicking counter clockwise. In neutral it spins both ways with no resistance. All switches seem to be working fine and now that ti is in the driveway it still does the same thing. Any pictures videos diagrams info and assisstance is greatly appreciated.

 

[Bondo]

Re: lost forward and reverse on mercruiser stern drive

hi again everyone; Mercruiser 165hp model number 21653 serial number 3465185. i think its a prealpha drive? I got towed in the other day. I had the boat running very well for the morning fishing with no problems. Then when on return home and engaging the trottle into forward position the drive made a grinding sound but still was somewhat in forward gear. I changed to reverse thinking seaweed (although i knew there wasnt any) then back to forward with the same outcome. I checked the linkages and all seemed well. Upon wiggling the shift cale and other parts of linkage, the gear makes no attempt for forward now and no grinding. When i jumped in the water to turn the propeller counter clockwise while the throttle was in forward gear. The propeller did turn with resistance and clicked in the counter clock wise rotation. The reverse also turned both directions with little force clockwise and a clicking counter clockwise. In neutral it spins both ways with no resistance. All switches seem to be working fine and now that ti is in the driveway it still does the same thing. Any pictures videos diagrams info and assisstance is greatly appreciated.

Ayuh,.... Drain the drive, 'n look for water or metal....

Then pull the drive, 'n see what's up...

 

[Grub54891]

Re: lost forward and reverse on mercruiser stern drive

I think you cooked the upper half of the drive.The shift will still work but the upper is toasted.

 

[james_dorion]

Re: lost forward and reverse on mercruiser stern drive

i drained the oil it looked lie oil although it was dark with some lighter streaks in it. I saw no debris of metal.. Now trying to take the trim tab screw off. Seems someone has stripped it. Going to try some easy outs but would like better suggestions.

 

[Bondo]

Re: lost forward and reverse on mercruiser stern drive

i drained the oil it looked lie oil although it was dark with some lighter streaks in it. I saw no debris of metal.. Now trying to take the trim tab screw off. Seems someone has stripped it. Going to try some easy outs but would like better suggestions.

Ayuh,.... Melt it(the tab) with a plumber's torch...

 

[james_dorion]

trouble removing trim tab

trouble removing trim tab

i have a mercruiser with a pre alpha outdrive 1972 to 1978. Im trying to drop the lower unit of the drive but i cannot get the screw loosened on the trim tab. 3/8 doesnt fit 7/16 fits but sloppy turning left. i think im going to try easy outs but seems my luck isnt working. What is the sure fire way to get this off.

 

[abrx7]

Re: lost forward and reverse on mercruiser stern drive

Follow this thread: http://forums.iboats.com/showthread.php?t=561830

 

[Bondo]

Re: trouble removing trim tab

Re: trouble removing trim tab

i have a mercruiser with a pre alpha outdrive 1972 to 1978. Im trying to drop the lower unit of the drive but i cannot get the screw loosened on the trim tab. 3/8 doesnt fit 7/16 fits but sloppy turning left. i think im going to try easy outs but seems my luck isnt working. What is the sure fire way to get this off.

No reason to start another thread,... I already answered yer question in this 1...

 

[james_dorion]

Re: trouble removing trim tab

Re: trouble removing trim tab

sorry the last post about removal of trim tab was suppose to start a new thread.
I took the top cap off the drive unit and all looked ok gear wise. You can see the gears turning each way when in forward gear like i said earlier.
I did notice the engine was very hot that day it broke down. I checked the motor oil and it is grey and sludgy. Not like oil is suppose to look. Oil was new at the beginning of season. I still never got the trim tab off but now i guess i have to pull the whole drive? It looked like my water was flowing through the water pump. Again the boat was running very well that day but i did have a problem getting past 3800 rpm

 

[abrx7]

Re: trouble removing trim tab

Re: trouble removing trim tab

Now it sounds like the drive isn't shifting into gear all of the way. Have you messed with the lower shift cable at all?

 

[james_dorion]

Re: trouble removing trim tab

Re: trouble removing trim tab

i played with the shift cable just enough either way to give me just forward or that day i would have reversed all the way home if i could have forced it into gear. Its not the interrupt switch bevause that was working fine also. I moved the shift shaft oth ways and you can feel it shifting gears and feel the difference out of neutral but it does not lock to where i cannot turn it. I hope this helps.

 

[abrx7]

Re: trouble removing trim tab

Re: trouble removing trim tab

Couple questions... how old is the boat and do you know if the lower shift cable has been replaced? If it was... when?

 

[james_dorion]

Re: trouble removing trim tab

Re: trouble removing trim tab

the boat is old 1972 to 78 ive never changed the shift cable but the shift cable seems to be working with ease forward and reverse and is changing the gears in the lower unit. im starting to think it is coming from where the drive meets the motor???

 

[abrx7]

Re: trouble removing trim tab

Re: trouble removing trim tab

If it was where the drive meets the motor then you would be hearing all sorts of noises whether the drive is in gear or not. You need to pull the drive and inspect. I think your shift cable is bad but that's just my 2 cents.

 

[Don S]

Re: trouble removing trim tab

Re: trouble removing trim tab

I did notice the engine was very hot that day it broke down.

Before you spend a lot of time taking the drive apart, remove the drive from the boat, and look into the coupler through the gimbal bearing. The splines may be missing. No splines, the drive isn't turning and the water pump isn't pumping. AKA overheat.

Gray and sludgy oil is another problem, was the oil level way over full ? That alone would cause your WOT problem

 

[james_dorion]

Re: trouble removing trim tab

Re: trouble removing trim tab

well Don i hate it when youre right. You make all this seem so simple how you troubleshoot without seeing the problems and always get it right. I value your knowledge. There was a whole mess of steel in the coupler. Not good!! I should always expect the worst. I was hoping it would have been the cable. So any good links to follow on how to get this part fixed. Looks like the motor has to be pulled but i hope there is an other way. Any reasons why this ripped apart...

 

[Don S]

Re: trouble removing trim tab

Re: trouble removing trim tab

You replace the coupler to fix it, and yes you have to pull the engine.

Any reasons why this ripped apart...

Sure, usually it's due to lack of maintenance. Not being greased yearly, or the engine being way out of alignment, possibly due to rotten transom or stringers, or even failed motor mounts.
You do pull the drive and grease the splines and check the alignment every year don't you?

 

[james_dorion]

Re: trouble removing trim tab

Re: trouble removing trim tab

never took the drive off before to grease anythhing in there. Changed all fluids religiously but seems i like to learn about this stuff the hard way. I knew i had to replace the coupler not repair it. Now im i need of a link to the manual to do this

 

[Don S]

Re: trouble removing trim tab

Re: trouble removing trim tab

Can do that too, http://www.4shared.com/office/WwMmi_rD/02__Eng__Drives_74-77.html?