Johnson &Evinrude jumping out of gear 51/2 to 40 hp older motors

[Anonymous]

Once fully engaged into gear (with out any remote controls connected) what keeps the dogs engaged and motor in gear?

[lindy46]

Anonymous wrote:

Once fully engaged into gear (with out any remote controls connected) what keeps the dogs engaged and motor in gear?

Frank answered that in the second post: the shift linkage and detent

[Anonymous]

OK, now as Paul Harvey would say this is the rest of the story. Case #1 The gear foot has a new looking clutch dog and new looking dogs on the gears and pops in and out of gear. The linkage adjustment at the shift lever was checked and the detent pin was correct. I went looking for the problem by disassembling the gear case and inspecting the linkage for wear. I checked the gear and cradle, fork nubs and linkage hole in fork, lower shift rod elbow that mates to the fork. No wear was found when checking all contact points in the linkage in the gear foot. No looseness in the linkage was found in the gear foot, for lack of a better word the linkage was “snug”. Reassembled the gear case and then removed the inspection cover the the side of the lower unit exhaust housing and checked the linkage connector, it was fully assembled correctly. Before closing the cover, I grabbed the linkage and tried to move it up and down looking for any play and found I was able to move it perhaps 1/4 of and inch. Next I pulled the power head to check for the source of the play. The shift lever where it enters the housing was not loose or worn. The upper shift rod to lever connector (swivel 303702) was not loose. The connector(swivel 303702) to shift rod lever(377188) was not loose. But the lever (377188) to adjusting lever shaft (277871) assembly was loose. The shaft was not worn, but the lever was worn where it mates to the shaft. Because the little lever(377188) is $40.00 , I did a outside the box repair. The lever is split and held on tight to the shaft by a cross drilled screw that squeezes the split lever tight on the shaft. But because of the wear it could not take up the wear on the inside diameter. I made up a .002 brass shim that I slid into place between the shaft and lever to take up the slop., then the screw could clamp the lever tight to the shaft. Now the linkage has no play or looseness and the clutch dog is fully meshed with the gear dogs and will not vibrate or hop out of engagement. Case #2 This motor that was assembled with rounded off clutch dog and the very worn dogs on the gears that would not pop out of gear. I checked the linkage for play through the side cover. You could not move the linkage, it was snug. My conclusion is that the very most important thing to prevent the popping out of gear is a snug, absolutely no play in the linkage from the gear all the way to the shift lever. The contact area of engagement between the dogs is very small.

[Anonymous]

Frank got it right on what holds the motor in gear. If you fix it by replacing the clutch dog and gears, but have loose linkage it will work for a little while if you are lucky and then the problem will come back. I hope by sharing my test that this will help when this problem presents it self. Also if shifted correctly with a snug linkage and at low RPM and properly maintained with the correct amount of oil and no water these clutch dogs will likely never wear out no mater how many shifts are made or what prop (aluminum ,bronze,stainless steel) is used. IMHO.

[garry-in-michigan]

Scott-Atwater had five years to find a way around OMC’s gear shift patents, and they made good use of the time. OMC came up with several ways to try to overcome peoples instinct to “ease it into gear”. Engineers are always surprised by the different ways people manage to destroy their outboards. Witness how many owners manuals you find on eBay that look like they were never opened . . . LOL

[johnyrude200]

One thing I didn’t hear anyone say (and I admit some of the really long responses I only skimmed…appologies if this has been said), is that with the worn linkages/slop, particularly at the shifter, the yoke that goes from the powerhead down to the shifter, and then the shift linkage that is in the exhaust housing, I have found that shimming the shift lever stud and the little knob hanging off the actual shift lever can fix these issues.

So what I am saying is pull the shift lever off and put a couple of washers behind it. This will take the slop out of where the shifter yoke engages the spring that tensions the shift lever against the shifter cam (which holds the motor in F-N-R). You can also put a nylon bushing or if not available wrap electrical tape over and over the little stud which follows the shifter cam. The shifter cam is the thing that the shift lever follows and holds the motor in gear. It is located on the starboard side and you can see this if you look at the shift lever.

The 25hp motors are most sensitive to wear and tear to these components. The 18 and 20 tolerate it more.

So the newer style gearboxes with spring loaded ballbearings in the prop shaft, those motors are better but jump out of gear when everything is worn more easily.

You really can’t put an older fastwin gearcase on a 1969 or newer style 18-20-25 because they lacked this improvement. Generally the easiest way to identify which gearboxes have these detent ballbearings is if the anti-ventilation plate is round or square at the back of the fin. The round ones are the older style, the square are the ones with the detent.

If you are lucky enough, you can get your hand on the rather uncommon 3-lug gearboxes for the 22 c.i. motors. Once you have one of those, you won’t have to worry about any of these issues again regardless!

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