Merc/Mariner 15 two stroke neutral in/out gear adjustment?

[Max...]

Anyone know how to adjust this? I've had one that had a very defined clonk in out but the current one is a bit vague.

[Fenlander]

Max my Mercury 15 service thoughts are gradually fading from instant recall but isn't the setting on yours the cable adjustments where the twistgrip control cables come back to the nylon pivot?

[Max...]

That was my vague memory too. Is it a case of loosening them (like bicycle brake cables) to allow more slack? I'm on the river at this very moment on a pre Devon shake down so any quick help appreciated!

[Fenlander]

Well I remember one cable pulls the nylon wheel one way.... and the other the opp way. So I guess you would bias the cable setting balance towards an even "throw" from neutral to fwd and neutral to rev... then set for minimal slack???

Sorry for the slow response! Just out in the garage drilling the transom so I can bolt the OB on for Cornwall fortnight.

[Max...]

Cheers David. Tried some adjustments riverside but not improved much as I'm guessed really. Will fiddle with it on the muffs with manual to hand.

[Max...]

Bugger - cannot find the relevant manual pages - anyone offer any help with this?

Is it just adjusted by the cable tension or the gear shift shaft thingy - seem to remember this when I last had the leg off for the impeller a few years back...

[Fenlander]

In older and other models there was a gearshaft clamp found through a hole with large runner grommet which needed loosening before dropping the gearbox to do an impellor. But as far as I remember on yours to free the rod to drop the gearbox there is a ball joint and spring clip seen down the left side of the engine under the hood right near the powerhead base.... in which case I assume there is no midway clamp to adjust.

See 1:09 into this video...

https://www.youtube.com/watch?v=Aij0F8MHwlQ

I think if you have this clip you don't have the mid shaft clamp?? Then the only setting would be the cables.

To me logic says on the side pulley to loosen one cable and tighten the other (or vice versa) will align the mid posn on the twist to the neutral on the gearbox

[Max...]

Thanks David - will check it out - I found the old manual link too:

Boatinfo - Mercury Service Manual for 6-8-9,9-10-15 hp

Your logic is shared - still feels indistinct though - you can think you have clicked into neutral but it's still just ticking over in gear...needs to go right round to reverse it seems. And IIRC if left in this [think it's in neutral zone] it will actually start in gear as happened yesterday.

[Fenlander]

That sounds more like slack somewhere in the cable run.

I remember all three of mine with that arrangement had quite a distinct neutral easily found on the twistgrip... as I guess yours has been up to now?

The error of being able to start in gear must give a clue to your issue but I forget how that interlock works so can't offer opinion.

[Max...]

Bah - now tried it slacker, tighter, loosened one/tightened other - seems just the blooming same whatever I do to the cables...

[Fenlander]

That gear change link as in the video is secure I assume??

[Max...]

Yes, all correct.

I think it's due to point 13/d (page 218) below - the engine has always been like this and I did not change the distance when doing the impeller a few years back so possibly it was maladjusted?

Boatinfo - Mercury Service Manual for 6-8-9,9-10-15 hp

[Fenlander]

Ahh so you can change the length with a screw in rod... but I'm assuming only with gearbox off?

[Max...]

Yep. And dropping the leg is the last thing I fancy doing at this time! I'll live with it and sort it come winter I guess.

[Fenlander]

Do you think you could dial out the leg adjustment error by making a compensating change to the cables on that pulley??

[Fenlander]

On reflection perhaps best not try my idea of post #15 above. It could work but best not to try and get it working with compensating errors.

OK Max had time to give this some thought. If you wanted to prove the issue was the adjustment of the gear rod within the leg...

Refer to the repair manual linked above.

Put it in neutral using the tiller twist but referring to making sure the gearbox is truly in neutral with a free spinning prop and forget the neutral marking on the tiller... then referring to the right hand page of 217/260 lower diagram remove clip/pin "C" and allow the change rod to adopt whatever relaxed neutral posn it wants again checking for a free spinning prop.

Set the twistgrip to its marked neutral posn. Then check if the pin of clip C can be pushed into the eye of the gearchange rod. If it can't then at least you know it's the rod adjustment and not something else. If it lines up then your problem may be elsewhere.

While doing that refer to the numbered exploded diagram on page 221/260. Pop off the nylon cup of rod "33" from the ball of gear "2". Then check gearchange cross shaft "32" is free to pivot. If not free and lubricate (lubricate anyway even if it turns).

Apparently shaft "32" can get partially seized which prevents free movement of the gearchange rod and therefore stops the gearbox falling easily into the detent posn of fwd/rev/neutral..

[Max...]

Thanks as always David. Will look at all that in the next day or two. Wish we were closer!

[Max...]

Originally Posted by Fenlander

Put it in neutral using the tiller twist but referring to making sure the gearbox is truly in neutral with a free spinning prop and forget the neutral marking on the tiller... then referring to the right hand page of 217/260 lower diagram remove clip/pin "C" and allow the change rod to adopt whatever relaxed neutral posn it wants again checking for a free spinning prop.

Set the twistgrip to its marked neutral posn. Then check if the pin of clip C can be pushed into the eye of the gearchange rod. If it can't then at least you know it's the rod adjustment and not something else. If it lines up then your problem may be elsewhere.

Seems this could be it - the rod should be about 5mm longer in adjustment I think - just wondering (I should be so lucky!) if there is any way to adjust without dropping the leg...

Originally Posted by Fenlander

While doing that refer to the numbered exploded diagram on page 221/260. Pop off the nylon cup of rod "33" from the ball of gear "2". Then check gearchange cross shaft "32" is free to pivot. If not free and lubricate (lubricate anyway even if it turns).

Apparently shaft "32" can get partially seized which prevents free movement of the gearchange rod and therefore stops the gearbox falling easily into the detent posn of fwd/rev/neutral..

This is all nicely greased and appears to be moving freely. The cup seems reluctant to pop off with a screwdriver and I'm wary of cracking it...

[Fenlander]

>>> appears to be moving freely. The cup seems reluctant to pop off with a screwdriver and I'm wary of cracking it..

Fair point it will have some degree of age hardening I'm sure so you don't want to add to the problems.

>>>wondering (I should be so lucky!) if there is any way to adjust without dropping the leg...

From the manual procedure to set this length seems there is no locknut on the thread that allows the length to be changed so were it a straight rod I guess you could just twiddle... but it looks to have a dog leg at the bottom and that slight kink at the top. No harm in a gentle try I guess??

I know this is annoying but better to be a simple daft issue than the rod be right and something in the gearbox failing.

Appreciate you'd rather not drop the leg but it's not like you have the impellor to swap as well. Just to pull the leg enough to adjust the rod is easily well under an hours work.

As you say if you were nearer... I'd *make* you call round and have it done.

[Max...]

We're on the same wavelength - leg dropping today...