1969 40 HP Big Twin Shift adjustment

[byacey]

This motor doesn't want to engage into reverse, I have to manually push the shift lever all the way back, and it just engages slightly. Forward however, engages close to the neutral position. It appears the shift rod is not adjusted correctly in relation to the detent positions on the shift lever. I have double checked the brass link, and both the upper and lower rod are correctly inserted. Is there a length adjustment on the upper rod, or a spline adjustment or something similar for the shift lever to upper rod?

 

[Paul Moir]

Re: 1969 40 HP Big Twin Shift adjustment

You can adjust the shift handle itself to line up the detents better. I don't know if you'll find enough adjustment in it, but it's worth a shot. You have to loosen the pinch bolt on the handle in addition to the slider bolt.<br />If that doesn't solve it, likely something's bent. That can happen if once someone tried to force it into gear when the engine wasn't running (and the dog ears hung up on the gear ears).

 

[byacey]

Re: 1969 40 HP Big Twin Shift adjustment

Which are these two bolts? There is a 7/16 head bolt on the shift arm just before it goes into the motor leg, by the base of the power head. The only other adjustment that I see is the two allen head machine screws that attach the shift handle to the offset linkage, but I can't see that affording any adjustment.

 

[Paul Moir]

Re: 1969 40 HP Big Twin Shift adjustment

Ooops, sorry, I was thinking of the later 70s 40hp engines when I was talking about the pinch bolt. I don't think your 40hp has one.<br /><br />Have a look at the base of the shift handle shaft where the pin follows the brass lockout bar. It should have a bolt running through it into the next peice. Loosen that bolt and there should be some adjustment there, but it might not be enough.<br /><br />I take it the phillips screw on the side of the skedge on the lower unit wasn't accidently removed? If so, the shift cradle in the lower unit can be out of place. Look for signs that screw was removed.

 

[byacey]

Re: 1969 40 HP Big Twin Shift adjustment

No, I had the gear case open to inspect the dogs,(Which had a little wear on the corners, but not excessive) and it all went back together the way it should. By the way, do you know if the dogs can be built up with hard surface weld, and re-machined? <br />If I can't get enough adjustment to get the shifting working as it shoul, I just might make a new shift rod link out of stainless instead of brass.

 

[Paul Moir]

Re: 1969 40 HP Big Twin Shift adjustment

Unfortunately, I think the weak point for bending would be up around the bell-crank (just underneath the powerhead).<br />I've heard of people welding up there dogs and regrinding them, and I've also heard of people just grinding them down a bit. Also, somtimes you can flip them (I'm pretty sure this is the case with your 40hp) and if the ears on the forward gear is bad, you can swap the forward and reverse gears. The bearing in the forward gear needs to be pressed out but it's not difficult.<br />Finally, I belive the dog is still available from BRP for about $90 Canadian. So you've got lots of options there.<br /><br />A new shift rod link wouldn't be a bad idea at all. Easier than pulling the powerhead, etc.<br /><br />I think you should have the later gearcase with the drilled propshaft and detent balls for the clutch which provides positive shifting. They usually don't have the bad clutch dog problems like the earlier ones.

 

[byacey]

Re: 1969 40 HP Big Twin Shift adjustment

My Gearcase doesn't have the detent balls; so this must be an older unit. The model is a 1969 #40952R.<br />Maybe I'll try flipping the dogs around if they start causing trouble someday. I think I'll design a shift link that is adjustable, shouldn't be too difficult.

 

[jameswilson95]

Re: 1969 40 HP Big Twin Shift adjustment

I have the same model evinrude as you. Did you disconnect your shift cable from the shift lever and manually try shifting yourself. And by the way my engine has the detent balls on the prop shaft. I think I read somewhere that this was a modification which should be carried out.

 

[jameswilson95]

Re: 1969 40 HP Big Twin Shift adjustment

What part of alberta are you from? I'm in edmonton.

 

[byacey]

Re: 1969 40 HP Big Twin Shift adjustment

Hi James, I'm just north of St. Albert a couple of miles.<br />I did disconnect the shift cable, and if I manually push the shift lever as far back as it possibly can go, It grinds slightly as if the dogs were just beginning to make contact with the reverse gear.

 

[byacey]

Re: 1969 40 HP Big Twin Shift adjustment

If anyone has the service bulletin outlining the detent ball upgrade, I would be interested in seeing this. Would that require replacing the prop shaft, or is it a simple matter of drilling a shallow detent hole and then putting a spring and ball on the "dog's collar"?

 

[lark2004]

Re: 1969 40 HP Big Twin Shift adjustment

The hole goes right through the prop shaft, and has one spring with a ball at each end. The hole is drilled right in the middle of the splined section of the shaft. I don't know off hand exactly what diameter the hole is but here is an exploded view of the gearcase, <br />

<br /><br />And just in case, this is the shift adjust that my manual shows on the lever.<br /><br />

<br /><br />I hope this helps.

 

[Paul Moir]

Re: 1969 40 HP Big Twin Shift adjustment

The drilled hole was a little larger than 1/4". I clearly remember using 0.250" balls for the detent. The clutch dog has a groove it's splines so it 'clicks' into neutral too.<br /><br />PS - I'm a one-time resident of just SW of the Commonwealth Stadium. Small world eh?

 

[jameswilson95]

Re: 1969 40 HP Big Twin Shift adjustment

I'm taking the gearbox of my motor (again) I have a leak in there somewhere that I am trying to locate. I will be opening up the prop shaft assy cover to clean the gears and shaft, etc. If you want to have a look at the parts just email me at jameswilson95@hotmail.com and we can set up a time for you to come and have a look at the detent hole, spring and balls.

 

[byacey]

Re: 1969 40 HP Big Twin Shift adjustment

Thanks Lark2004,<br />The shift lever looks a little different on my motor.<br />The shift lever is held on with a couple of Allen Head Machine Screws, and they don't allow any adjustment at all.