mercruiser 165 problems shifting gears and stalling

jrouse5 · Jun 24, 2010

I have a 1978 Mercruiser 165 I/O. I bought it from my father. When I got it the boot that goes around the drive shaft was busted and the gimble bearing was going bad. I took all that off and replaced the bearing and the boots that go around the exhaust and drive shaft. I couldn't figure out how to get the cable out of the other so i just left it. It looked good anyway. I got it all back together and it didn't want to go into reverse without stalling out. I didin't run it before i replaced the bearing and boots so i don't know how it was acting before that. I got inside the engine compartment and watched the lever that activates the micro switch to stall the engine and figured out how it worked a little better. I tried adjusting that brass bead that is threaded on the rod to move it a little so it would not come to the end and pull the switch to cut it out. It will not come into adjustment. It will either go all the way into forward and half way into reverse where the gears grind and will not fully engage. But i can't seem to get it to stick in reverse all the way. If i tighten that cable it just wants to stall the engine. Any thoughts?

Fishermark · Jun 24, 2010

Re: mercruiser 165 problems shifting gears and stalling

Welcome aboard!

Time to do two things:

1. Download the service manual for free - look at the top of the page for information for DIYs - (also in the "adults only" section).

2. Buy a new shift cable and shift cable boot and install and adjust it per the manual.

jrouse5 · Jun 24, 2010

Re: mercruiser 165 problems shifting gears and stalling

I wish i would have known that. Is there any other thing that could cause it? I just replaced that gimble bearing and those boots. Do i have to replace those again when the cable is replaced? Also, is it difficult, compared to that bearing? Anyway, thanks for the help.

stonyloam · Jun 24, 2010

Re: mercruiser 165 problems shifting gears and stalling

jrouse5 said:
I wish i would have known that. Is there any other thing that could cause it? I just replaced that gimble bearing and those boots. Do i have to replace those again when the cable is replaced? Also, is it difficult, compared to that bearing? Anyway, thanks for the help.

The cable is the only thing you have to replace. "adults only", #9, Manual #6, section 4-A will walk you through the procedure. Will have to pull the outdrive, nothing more. Need a special tool to remove hex nut on cable. read this: http://forums.iboats.com/showthread.php?t=394875&highlight=shift+cable+tool post #4 to see one idea for making one (two sockets welded together works too). Good luck.

nuboat2me · Jun 25, 2010

Re: mercruiser 165 problems shifting gears and stalling

stonyloam said:
The cable is the only thing you have to replace. "adults only", #9, Manual #6, section 4-A will walk you through the procedure. Will have to pull the outdrive, nothing more. Need a special tool to remove hex nut on cable. read this: http://forums.iboats.com/showthread.php?t=394875&highlight=shift+cable+tool post #4 to see one idea for making one (two sockets welded together works too). Good luck.

I used the manual and it was spot on... My SIL had the tool (Two sockets welded together) It took us about 2 1/2 hours. Just be sure that when you are ready to pull the old cable out, tie wire, string, LONG zipties from the old to the new. Sure wish I did...

It will be MUCH easier to pull the new one thru. Oh and take some photos for reference.

I also found the shift interrupt wire was cut. Apparently the PO had problems with it stalling going into gear. He just cut the wire. Soon enuff, the original cable failed. Thus the replacement. Re connected the wire to the coil and water test happens tonight!!! (If the rain holds off)

Sorry so long..

Happy Boating!!!

jrouse5 · Jun 26, 2010

Re: mercruiser 165 problems shifting gears and stalling

So, I guess the majority says it is the shift cable. I can get it adjusted where it will go into forward and no reverse or half way into reverse and halfway into forward. But no full reverse. Just wanting to be sure it is nothing else like gears bad or anything like that. Thanks again all.

jrouse5 · Jun 26, 2010

Re: mercruiser 165 problems shifting gears and stalling

Also, does any one know the part# for this part? It is 1978 Mercruiser 165 w/a Straight 6 engine. Thanks again. Josh

marinetech77 · Jun 26, 2010

Re: mercruiser 165 problems shifting gears and stalling

Just to be sure before you replace a shift cable that might not necessarily be bad, check the routing of the shift cable. If the cable is not routed properly it will not operate as it should. The cable should have long sweeps and no sharp curves. If you were able to easily adjust the barrel, the cable has been replaced before. The older cables had the barrel crimped on and were a pain to adjust at best.Replacing the cable is a 2 person job for the novice. 1 to feed the new one in 1 to route cable through transom assy. Get a long handled pair of needle nose pliers. Welding two 9/16 sockets together works great for the cable. Just remember to put your shifter in forward before removing drive. If you are going to take the time to do the cable take an extra 15 mins and install the upgraded shift shaft bushing kit. The cast aluminum shift arm on top of the shift shaft comes off very easy with a chisel and a few blows of the hammer, you will not hurt the stainless shift shaft. I have replaced well over 100 of these cables.

Fishermark · Jun 26, 2010

Re: mercruiser 165 problems shifting gears and stalling

You will need to buy the new style cable that screws in from the aft side. If you still have the older style cable that screws in on the forward side of the bell housing, then you will need to tap the threads to screw the new cable in. Be sure to get the right tap - it is a straight tap - not tapered. I don't have the exact spec for the tap in front of me... but do a search and you will find it.

jrouse5 · Jun 26, 2010

Re: mercruiser 165 problems shifting gears and stalling

marinetech77 said:
Just to be sure before you replace a shift cable that might not necessarily be bad, check the routing of the shift cable. If the cable is not routed properly it will not operate as it should. The cable should have long sweeps and no sharp curves. If you were able to easily adjust the barrel, the cable has been replaced before. The older cables had the barrel crimped on and were a pain to adjust at best.Replacing the cable is a 2 person job for the novice. 1 to feed the new one in 1 to route cable through transom assy. Get a long handled pair of needle nose pliers. Welding two 9/16 sockets together works great for the cable. Just remember to put your shifter in forward before removing drive. If you are going to take the time to do the cable take an extra 15 mins and install the upgraded shift shaft bushing kit. The cast aluminum shift arm on top of the shift shaft comes off very easy with a chisel and a few blows of the hammer, you will not hurt the stainless shift shaft. I have replaced well over 100 of these cables.

When I adjusted it, the barrel seemed tight. I had to vice grip the steel part right before the threads, and take pliers and twist the brass barrel to turn it. I also got some silicone spray down the cable cause it seemed tight causing switch to kill the engine, when i got it back together, it wouldn't even move the switch to let it go in gear smoothly, maybe i got it too slick, but even then, it still would not go in both gears fully. Also, I buy a lot of my parts from e-bay, cause the seem to be considerably cheaper that the local boat shops, could someone tell me which one i need? And if i need one with the upgraded shifter like the last person said, does anyone know what that one would be as well? Thanks again.

Fishermark · Jun 27, 2010

Re: mercruiser 165 problems shifting gears and stalling

I'm pretty sure the only shift cable still available is the newer style. You will have to look and see which style you currently have. Here is a pic showing the difference - look and see where it screws into the "helmet":

jrouse5 · Jul 2, 2010

Re: mercruiser 165 problems shifting gears and stalling

One last thing that I thought of. The problems of not slowing to let if go into gear and not fully engaging wouldn't have anything to do with the boat being out of water and on the muffs would it? Just something that i thought of. Didn't know if the lack of resistance on the propeller would make any difference.

jrouse5 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

ttt

Eric 3.7LX Alpha 1 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

The cut off switch works when shifting the engine out of gear back into neutral, only, and only in the water. It does not activate on the trailer. The shift cable can not be looked at to determine if it is good or bad, most of the time they look good.

The torque of the engine in gear is too much for the cable to disengage it without the cut off, which will kill the engine for a second or two so there is no torque at that moment and the shift works smooth.

When the cable is worn, it adds additional tension on the shift cut out switch causing it to stall the engine. Hopefully you were able to download the manual before they were removed. The shift cable needs replacing and as mentioned above I would also replace the shift shaft bushing/seal in the bellhousing, The new redesigned one is much better.

Good luck with it.

jrouse5 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

This is what i was wondering. I bought it from my dad. It sat 2 years. I gave it a tune up and changed impeller and what not, then I was just checking to see if it would go in gears and all that good BEFORE i went to the lake. This is when it was acting up. I still have not taken it yet, because it is a little bit of a drive. So do you think it will be fine? or do i just need to take it to the lake and see, or just order the cable and put it in. I checked it out of the water. Thanks again.

Eric 3.7LX Alpha 1 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

Did you try shifting before you did the impeller? was it the same or different?

If when you shift it from gear to neutral on the trailer while running on muffs (use caution with the prop spinning outside the boat) have someone look at the cutoff switch, It should not move. If it is- there is something wrong with it causing additional resistance to activate the cut off.

jrouse5 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

It does not move at all. So do i just need to reset the length of that barrel as i was reading in the manual to be 6" from the end of the link to get the gears where they should be? Also, i put some silicone lubricant down the cable. Then should it go in gear fully in both directions while on the muffs, but just not activate the switch, or will it still act up and not go in to gears fully unless in the water? I guess i could just adjust it to spec and take it to water and see what happens. I just hate to take a chance on being out of adjustment or something else wrong and tear the gears up. Any things to look for when i take it? Thanks again.

jrouse5 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

I didn't really check it because the first time i started it the gimbal bearing was bad and i shut it off pretty quick. But after I replaced that, it didn't want to go into reverse, it stalled the engine. I sprayed some lube in the cable and it quit activating the switch but by that time i had already messed with the adjustment think that it was just messed up. I didn't really know what i was doing, i was just noticing that it was pulling hard one way and moved it the opposite so it would quit pulling so hard on the switch. But i haven't set it to 6" yet and tried it again. Im sure the gears are strong like car rear end gears, but i didn't want to strain them too much, i mean it is a 78 model. Thanks again.

Eric 3.7LX Alpha 1 · Jul 11, 2010

Re: mercruiser 165 problems shifting gears and stalling

It is possible that when you reassembled the lower to the upper you might be one notch off on the spline shift shaft on the lower unit. try adjustment first.

Here is another diagram I saved from online that might help with adjustment:

jrouse5 · Jul 12, 2010

Re: mercruiser 165 problems shifting gears and stalling

When putting the lower unit back together, how exactly do you know how the shift mechanism is supposed to go? I just kind of lined it up with the way it looked like it fit. Is there a certain spot that it is supposed to be? Thanks again.

mercruiser 165 problems shifting gears and stalling

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