big clunk when driving

[foxy510]

almost feels like i hit something when driving for a while it will surge /clunk whatever , have a 100 evinrude, from my searches it sounds like clutch dog , my prop is a little out of wack could that be the problem? also fuel coming from vent in my driveway on hot days .. i filled up to top im thinking over filled? sorry for silly questions , new boat...

 

[Chris1956]

Clunk is likely from shift dog. See if you have it adjusted correctly. Not sure what you mean by "fuel coming from vent". Sorry

 

[racerone]

Not all 100 hp are the same , a model # must posted.

 

[GA_Boater]

:welcome: aboard.

When you fill the tank, stop when it clicks off. You are not leaving air space for the gas to expand by filling it to the top.

 

[F_R]

A harsh clunk like you hit something is the classic description of a worn clutch dog, and possibly forward gear. A beat up prop may shake, slip, or vibrate, but not clunk.

 

[gm280]

I have to concur with the clunk sound being from the clutch dog. However, I'd fix all those things you mentioned as soon a possible for a few reasons. The clutch clunk will not heal itself and the longer you run it that way the more other parts will suffer and prematurely wear as well. You could have already ruined the gears now as well. Next is your prop that you already stated that it is not running right. That too can wear the seals and bearings faster then usual. Either replace it or have it reworked and balanced. And then water intrusions will most certainly take over and...well... it get real ugly from there. Third is gas coming out of the tank vent. Obviously you did fill the tank too high. But of all your issues that one is the easiest to fix. Either remove some of the fuel, OR run the engine to consume some. And in the future, watch closely about over filling the tank.. Gas splashing out could lead to a fire on board and that isn't good...unless you are wanting to be rid of your boat and are having a bonfire with marshmallows and hotdog roast...