1998 Johnson 90 4cyl outboard shuddering

SavannahKen

Cadet
Joined
Jul 18, 2010
Messages
7
J90TSL engine
A couple of weeks ago while returning from a day out at sea we thought we hit a log or something in the water. The problem is that it kept happening every couple of minutes or so. I finally realized that the engine was shaking each time this happened. Someone recommended I check the fuel/water filter. Well the 98 SeaPro 170CC did not have one installed so I installed a canister filter. A local mechanic also suggested I check the gear/ throttle linkage and adjust it to the point where the gears engage shortly after moving off of neutral. I adjusted this a little but the problem is still occuring. The mechanic described the symptoms exactly how they were occurring so he has seen this before. Anyone ever experience this? I am spending more time working on this thing than I am enjoying the water this summer.
Thanks in advance.
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 1998 Johnson 90 4cyl outboard shuddering

Likely worn clutch dog/fwd gear ... usually caused by 'gentle' shifting.
 

SavannahKen

Cadet
Joined
Jul 18, 2010
Messages
7
Re: 1998 Johnson 90 4cyl outboard shuddering

Jim,
Expensive fix if this is a worn clutch dog/ forward gear problem?
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 1998 Johnson 90 4cyl outboard shuddering

Yes, gearcase metal doesn't come cheap.
 

SavannahKen

Cadet
Joined
Jul 18, 2010
Messages
7
Re: 1998 Johnson 90 4cyl outboard shuddering

Had the lower gear unit replaced with a re-built unit. Seals were worn and a ball of fishing line was inside. Timing was way off too. New impeller, new seals, adjusted timing, adjusted throttle and shift linkage and all is good. 1,400 bucks. Time to go and enjoy the boat again....
 
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