94 johnson 150 fast strike shakes at slow speeds

[ndboatguy]

Hi guys, im new to the forum and just got my first boat, its a 94 glastron with a 94 johnon 150 fast strike. Everything seems to be runing excellent, except i noticed yesterday tbat when i was just idling around the lake that the motor shakes a bit , to where u can feel it thru the steering and thru the boat also. THis only happens at slow speeds, roughly 5-7 mph. Once you give it any throttle it goes away, i also noticed that it gets alot better almost to the point of dissappearing at slow speeds when i trim the motor up to inbtween 1/2 and 3/4 on the trim guage. <br />Since this is the first boat i have owned and first real time on the water for extended use i noticed it, and the dealer i bought it from said that they would take care of any problems that may occur. A friend of mine said he thought it might be turbulance, and he didnt think it was a problem but i just wanted to be safe.<br /> Also if i take the boat out of gear and just use the throttle the engine runs smooth as can be. Thanks <br />ndboatguy

 

[Bass Runner]

Re: 94 johnson 150 fast strike shakes at slow speeds

Sounds like the plugs or powerpack is laying down at idle, the motor will run smooth missing on 1 or 2 cyls in neutral but when you put it in gear then you will feel it.

 

[angus63]

Re: 94 johnson 150 fast strike shakes at slow speeds

If its from 1100rpm to 1600rpm, it's probably because of the transition from slow to medium jets. A sync and linc will minimize it but it's common in v6 loopers (mine too!).

 

[Reel Appeal]

Re: 94 johnson 150 fast strike shakes at slow speeds

ndboatguy,<br />What size is your boat? What size and pitch is your current prop?

 

[ndboatguy]

Re: 94 johnson 150 fast strike shakes at slow speeds

Glastron ssv 170 17 foot, not sure on the pitch as i forgot to look, and its parked at the lake.

 

[angus63]

Re: 94 johnson 150 fast strike shakes at slow speeds

V6 loopers known to run a bit lean during transition from low to medium speed. Some have attempted to richen with larger jets with some success. I have similar motor and chased the problem for a while. Now I simply avoid running continuously in the 1200 - 1500 rpm range. Spoke with many who have the same issue and have lived with it for over a decade without problems.<br />Good luck

 

[ndboatguy]

Re: 94 johnson 150 fast strike shakes at slow speeds

Thanks for the suggestions and ansers guys. I do have one questions. Can someone explain to me what a looper motor is? I work at a local car dealership in parts and have never heard that before.<br /><br />Thanks

 

[Daniel Beckman]

Re: 94 johnson 150 fast strike shakes at slow speeds

They runs like that...<br />A faststrike dont wanna run at low rpm, they wanna run like kings at high.<br />Got an fletcher arrowstreak 17 with an 92 fasstrike 175, and at low rpm the power shake it but i runs like a dream over 2500 rpm (knock on wood)