1981 35 hp evinrude shift dog???

[meatman]

I have a 1981 35 hp evinrude. Recently it began banging in forward during acceleration. (Just like I hit a log). Back down to low speed ok. Reverse is ok.
Last year changed water pump and thought maybe put something back wrong but had no problems first few trips after water pump repair. Also, while changing water pump I accidently pulled the shift rod screw but put it back in before moving anything. Again, no problems first few trips after.
This year the problem started. This forum and marine store say shift dawg. Maybe??? Here's what I found tonight. As I rotate the prop and shift from neutral to forward the shift rod travels full up no problem(water intake screen removed) until I rotate to one area of rotation and rod only travels part way even though the shifter is in full forward. Prop snug and hard to rotate and then a slight clunk and the rod goes full up and gear engages full forward.
Is this a shift dog problem?
If so I assume I have to pull the bearing carrier to get to it as well as all the seals, prop shaft, gears, etc and unscew that darn shift rod screw. Think I can do this without a flywheel puller if I heat it good enough and use bolts in the front support to pry it up and out? And any tips on how to align the shift rod screw if all else goes ok.
ANY HELP WOULD BE SOOO APPRECIATED.
thanks
meatman

 

[flabum]

Re: 1981 35 hp evinrude shift dog???

If you removed the shift shaft, it is possible you did not install it at the right height, not allowing it to shift fully into forward. Drain the iol and look for metal. It is likely you have a bad cltch dog and gear. The shift characteristic you described is normal.

 

[Joe Reeves]

Re: 1981 35 hp evinrude shift dog???

I'm somewhat at a loss to understand what you mean by aligning the shift rod screw or the need to dismantle the unit to remove the shift rod screw. There is no need to dismantle the lower unit in order to remove that screw. The shift rod screw is the one in back of the water intake screen (the connecting unit) and should simply be screwed all the way down.

The following may be of some interest to you.

(Jumping Out Of Gear - Manual Type)
(J. Reeves)

This pertains to lower units on all OMC manual shift outboard engines, or any OMC engine with lower units defined as a Shift Assist or a Hydro Electric Shift unit which incorporates a "Shifter Clutch Dog".

Within the lower unit, splined to the prop shaft is what is most often referred to as a clutch dog, hereafter simply called dog. The dog has at least two lobes protruding from it on both ends, facing both forward and reverse gear. The forward and reverse gears also have lobes built into them near their center area. When the engine is running, in neutral, the gears are spinning constantly via the driveshaft being connected directly to the powerhead crankshaft, but the propeller does not turn due to the fact that the dog is centered between the two gears, and the dog lobes are not touching either of the gear lobes.

When the unit is put into either gear, shift linkages force the dog (and its lobes of course) to engage the lobes of the gear. The lobes of the spinning gear grab the lobes of the dog, and since the dog is splined to the prop shaft, the propeller turns.

The lobes of the dog and gears are precisely machined, most with right angled edges that could be installed in either direction, and some with angles slightly varied that must be installed in one direction only (one end only must face the propeller). Dogs that can be installed in one direction only, if reversed, even if the dog and both gears were new.... would jump out of gear almost immediately. Keep in mind that the lobes are precisely machined with sharp angles!

Due to improper adjustment or worn shift linkages, but usually due to improper slow shifting, those precisely machined sharp edges of the lobes become slightly rounded. Now, with those lobes rounded, as the rpms increase, the pressure of the gear lobes upon the dog lobes increases to a point whereas they are forced apart (jumping out of gear), and due (usually) to the shift cable keeping tension on the engines shift linkages..... the unit is forced back into gear giving one the sensation that the engine has hit something, and the cycle continues.

Some boaters have the mistaken belief that shifting slowly is taking ixt easy on all of the shifting components..... Wrong! Shifting slowly allows those precisely machined sharp edges of the dog and gears to click, clank, bang, slam against each other many times before they are finally forced into alignment with each other..... and this is what rounds those edges off! The proper way to shift is to snap the unit into gear as quickly as possible.

********************
(Shifting With Engine Not Running)
(J. Reeves)

The following should explain the proper procedure for shifting into gear when the engine IS NOT running.

Pertaining to the manual shift models, when shifting into gear with the engine NOT RUNNING, the prop must be spun so as not to possibly have the dog and gear lobes run directly into each other.

To grasp this scenario, with your left hand form a "C" with your thumb and forefinger. Now, with your right hand, form a backwards "C" with your thumb and forefinger. Your fingers will represent the dog and gear lobes.

Slide the finger and thumb of your right hand alongside the thumb and finger of your left hand so that they overlap. This is the position of the dog and gear lobes when properly in gear.

Seperate that position, then butt the tips of the finger and thumb of your right hand up against the finger and thumb tips of your left hand. This represents having the gear and dog lobes directly facing each other. Should you atempt to force the engine into gear with this condition existing, damage to the shift mechanism will surely ocurr.

When time permits, visit my store (copy/paste) at: stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

 

[meatman]

Re: 1981 35 hp evinrude shift dog???

Thanks guys for the advice.
About the screw I mentioned removing, I accidently removed it last season when changing my gear oil and put it right back in without moving anything. The motor was shifting fine then and I was not reapiring anything. Just mentioned it in case anyone thought it might be related to the dog slipping. Sorry to have confused the issue.
I also now understand that my test with engine not running by turning the prop and seeing the shift rod fully engaging in some positions and not in about 1/3 of the rotation unless I turn the prop a bit more, is normal. I also assume that the connection nut inside my intake screen is non-adjustable so my water pump change and reconnect of the rod last season would not be the problem.
So it looks like cluth dog even though no metal in the oil. Perhaps just worn corners.
So again I would ask advice about tearing into the gearcase. Think I can pull the bearing carrier without a flywheel puller (just heat and bolts threaded into the face plate? And also, any tips on realigning the end of the rod when I get everything back together so I can reinstall the screw.
Sorry guys, new at gear case stuff and worried tearing into it for the first time.
thanks for your time and great replies,
meatman

 

[Joe Reeves]

Re: 1981 35 hp evinrude shift dog???

Pertaining to removing the carrier assembly, it may be possible to remove it using a slide hammer that incorporates a hooked rod end. However, assembling that lower unit may nesessitate obtaining a few special tools (purchase or borrow), and it does get somewhat involved.

I'd strongly suggest that you obtain a service manual that is specifically for that individual engine, as opposed to a manual that covers many models which can be quite confusing. The cost of the manual can be recovered at a later date should you decide to sell the engine.

 

[meatman]

Re: 1981 35 hp evinrude shift dog???

Thanks Joe. I'll ask the parts store for whatever tools I need. They already said I shouldn't need a flywheel puller but maybe they have a slide hammer. If all of this gets too complicated I'll give it up and hand over the lower unit to them. My buddy has manuals that we are using so hopefully we can manage it.
thanks again,
meatman