90 Hp Johnson "slipping"

[electroman27]

Hey guys, I have a 2003 Johnson 90 on my pontoon. On our last trip of the season it started "slipping" above about 2000 rpms. I say slipping because that's the best way I know to describe it...just like anything over 2000 was just free revving. The prop is brand new and we were in totally open water so I know its not spun. At one point on the way to the dock there was a kind of clunk sound like something engaged, then it acted fine. I had to slow due to traffic and when I throttled up after clearing it was the same thing again. This is my first outboard so I don't really know what I might be dealing with. Any ideas? How different are they than an outdrive as far as internals? Thanks for answering!

 

[racerone]

Re: 90 Hp Johnson "slipping"

I would start by checking the oil in the gearcase.---Also check if perhaps motor is mounted too high.

 

[Daviet]

Re: 90 Hp Johnson "slipping"

I don't think there is anything inside the lower unit to "slip", metal gear on gear.
Have you actually checked the prop to see if it spun the hub, it wouldn't be the first time a new part was defective.

 

[electroman27]

Re: 90 Hp Johnson "slipping"

I haven't marked the prop and checked it in the water again, since its quite a tow from my house, but I did pull it and look for anything out of the ordinary like rolled rubber ect. The engine is mounted where it was mounted at the Crest factory so I don't see that being a problem, not to mention we've used it many times with no problems. The clunking is what I'm concerned about. Could it just be a cable adjustment issue...perhaps not fully engaging forward everytime? I didn't think to try it in reverse.

 

[ondarvr]

Re: 90 Hp Johnson "slipping"

Sounds like the prop is slipping, but if you changed the type or brand of prop it could change how well it performs, some props do better than others when mounted higher. And yes it could be the cable adjustment, when this happens it normally bangs in and out of gear when it slips and it's very noticeable.

 

[electroman27]

Re: 90 Hp Johnson "slipping"

Will the mark test work to check the prop in a 55 gallon drum in the yard? The prop is the same Johnson/BRP part # that came with the boat. The clunk I'm attempting to describe is just that...not really a loud bang, just a slight sound, then it feels like the slipping stops, and I can throttle up and run just like normal. When I slow down the slipping starts again when I try to run over 2000 rpms.

 

[racerone]

Re: 90 Hp Johnson "slipping"

If you rev up a 90 hp motor in a 55 gallon drum the water will be gone in about 2 seconds.--Check the oil first.

 

[electroman27]

Re: 90 Hp Johnson "slipping"

Lol just checking. I've checked the oil level it's fine.

 

[ondarvr]

Re: 90 Hp Johnson "slipping"

When he said to check the oil he meant to look for metal shavings, if the lower unit is in bad shape you will see it.

 

[electroman27]

Re: 90 Hp Johnson "slipping"

Will do.

 

[boobie]

Re: 90 Hp Johnson "slipping"

Sounds like clutch dog and forward gear or loose shift linkage.

 

[electroman27]

Re: 90 Hp Johnson "slipping"

I have read some about clutch dog issues as well. I suppose I'm going to start with the simple and work my way in. The itch to get back out there is becoming unbearable.

 

[boobie]

Re: 90 Hp Johnson "slipping"

Keep on running it and see what happens.