25 hp Johnson wont stay in gear

Jim DeVries · Jun 11, 2006

I have a 1978 Johnson 25 hp engine that won't stay in gear at medium or high rpms. I have had the lower unit apart and the gears look in fine condition, the shift rod is adjusted properly. This was a problem I had last year too, so I purchased a used/rebuilt lower unit and the problem is back again with the new lower unit. Any ideas why this would happen again? Could it be the prop? What else might be going on that I haven't figured out yet? Any ideas would be greatly appreciated

JB · Jun 11, 2006

Re: 25 hp Johnson wont stay in gear

You are not gonna get a lot of Johnny help on the Merc/Mariner Forum, HB4D. Moving to The Johnson Troubles Forum.

diggerdan17 · Jun 11, 2006

Re: 25 hp Johnson wont stay in gear

is it actually popping out of gear or is it just revving up and losing speed at wot?...if its the latter then it may be a spun hub on your prop.

Jim DeVries · Jun 12, 2006

Re: 25 hp Johnson wont stay in gear

It feels like it is actually poping out of gear, you can feel and hear a clunk as it catches again if you keep pressure on the shift lever. I thought about the hub on the prop, but when I marked the position on the hub and prop, took it for a spin and rechecked the hub nothing had moved. I figured this would eliminate the idea that the prop was spinning on the hub!

jfm1 · Jun 12, 2006

Re: 25 hp Johnson wont stay in gear

try to adjust your shift cable make sure it goes all the way in gear, if it still does it then I would say its a bad clutch dog/foward gear

Jim DeVries · Jun 12, 2006

Re: 25 hp Johnson wont stay in gear

Do these go bad often? This is the second lower unit I have had on this motor and the problem is the same. My understanding was that the second lower unit was rebuilt and was supposed to be in good working order. If this is a common faliure then I will tear into the second one and see what is going on.

wilde1j · Jun 12, 2006

Re: 25 hp Johnson wont stay in gear

The clutch dog / fwd gear mating surfaces get rounded from 'gentle' shifting. You're undoubtedly in for a new clutch dog and fwd gear. And don't shift slowly!

diggerdan17 · Jun 12, 2006

Re: 25 hp Johnson wont stay in gear

do you have remote controls or is it a tiller ....if you have remote controls then try disconnecting the cable and shift manually....if it stops jumping out of gear all you have to do is adjust the cable properly.

Jim DeVries · Jun 13, 2006

Re: 25 hp Johnson wont stay in gear

Thanks for the idea. I have a remote control counsel and have disconnected it with no change.

DJ · Jun 13, 2006

Re: 25 hp Johnson wont stay in gear

You're in for a new clutch dog, as mentioned. "Easing it into gear" is the culprit for those going bad.

Jim DeVries · Jun 13, 2006

Re: 25 hp Johnson wont stay in gear

Thanks, that will be my next move. I appreciate all the input.

25 hp Johnson wont stay in gear

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