Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Shudder at idle, it shakes the boat
Posted by hm173 on 09/06/11 - 2:12 PM
#1
I have a 13' 87 SSL with an 05 40 hp Mercury outboard. The whole boat shudders at idle but with just a little bit of throttle the shudder goes away and it purrs like a kitten. I'd sure appreciate some advice.
Posted by Swamp on 09/07/11 - 7:28 AM
#2
Adjust your idle speed to get away from that resonant frequency?
Posted by hm173 on 09/07/11 - 7:50 AM
#3
Thanks Swamp. Is there an easy way to do this or should it be done in a shop?
Posted by Swamp on 09/07/11 - 8:19 AM
#4
Depends on how you define easy. If you're somewhat mechanically inclined, just have a look in the service manual. If it looks too hard or scary, bring it in to the shop.
Posted by rvschulz on 09/07/11 - 9:01 AM
#5
it would be nice to have some sort of tach attached to see if this is currently in the normal idle range. i have had motors that shook at idele, but that's how they were - it was running fine.
Posted by Metalcaster on 09/17/11 - 10:18 AM
#6
I would get a bottle of Quicksilver Quickleen fuel treatment. I had a problem with my 20 hp Johnson. It would often stutter when I tried to accelerate from being stopped. I added the recommended amount to my fuel and the problem has been gone for about 6 or 7 fishing trips now.
Posted by hm173 on 09/17/11 - 11:17 AM
#7
I'll give it a try, sometimes the cheap fixes are the best fixes! Thanks
Posted by Ice Cop on 09/17/11 - 11:08 PM
#8
If I understood your original question you have a vibration problem, not an acceleration problem. Forget the fuel additives and bump up the idle just a touch, should be a 1- screw adjustment, follow the moving parts while operating your throttle and see the stop screw it bottoms out against when at slowest speed, this is the screw that needs slight tweaking. You did not mention if it shudders at idle in nuetral or when in gear. same fix should apply just a touch more rpm's. I have found many engines are set correctly for idle rpm's but are set while out of gear. It should however be set with warm engine, in gear and NOT tied to a dock.