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1996 Johnson 48 SPL 2 stroke no forward but have neutral and reverse

J

James P

New member
Motor started reving like crazy about 6800 RPM's accidentally ground forward gear a little and put it into neural right away forward never got engaged. Now I try to put it in forward gear with motor on or off it won't engage but neutral and reverse work fine. I took lower unit off and I can engage forward neutral and reverse just fine but not with the throttle control. Any suggestion on what might of happened and how to fix it?
 
Having retired in 1991, I can't offer much help but this will get your post back on top of the list for others to see.

I can say that you should drain the lower unit to see exactly what kind of metal fragments exist in there... and if they do exist, the lower unit will require dismantling for inspection.

I assume that the unit was shifting properly at some previous point, and if so... did you have the lower unit off for some other reason before this took place... changed the shift rod height, whatever?
 
joereeves said:
Having retired in 1991, I can't offer much help but this will get your post back on top of the list for others to see.I can say that you should drain the lower unit to see exactly what kind of metal fragments exist in there... and if they do exist, the lower unit will require dismantling for inspection.I assume that the unit was shifting properly at some previous point, and if so... did you have the lower unit off for some other reason before this took place... changed the shift rod height, whatever?
Click to expand...
Sorry for taking so long to respond. Had a family situation I had to take care of that took a while. I have not adjusted the shift rod at all and now all of a sudden it it skips in forward but reverse and neutral are fine and there are no fragments in lower unit fluid. I figured maybe clutch dog but wouldn't it slip in reverse ad well?
 
No, a worn shifter dog which is affecting forward would have no effect on reverse. Check the centering of the shift cable as follows:

(Centering Shift Cable)
(J. Reeves)

When all is as it should be, the proper method to adjust the shift cable is to disconnect the cable from the engine.

Move the shift linkage on the engine to find the center of the play in neutral, and when found, leave it centered.

Now, grab the end of the shift cable sleeve, push and pull it to find the center of the play there, and center that play.

Adjust the trunion on the threaded portion of the shift cable so that the centered play of the cable lines up with the centered play of the engine's shift linkage. Install and lock the shift cable with the retaining clamp in that position.

That's it.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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(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 with manual shift engines have the mistaken belief that shifting slowly is taking it 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.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:
http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1

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(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.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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