Force 50hp idles Loud (knocking)

[jimjim11]

hello
i was pulling a wakeboarded this weekend and all of a sudden it started making a loud knocking noise. from then on i stopped pulling anyone. Now the motor idles loud with the knocking noise and will not run at full power. The motor will run and sounds fine at half throttle but if advanced past half it knocks loudly and stalls out. also it kinda looks as if the flywheel is wabbling slightly, and the nut on top is completly tight. any ideas ot what to look for?

the Engine is a Force 50hp (1990)

 

[jerryjerry05]

Re: Force 50hp idles Loud (knocking)

Start:broken crank(famous for that),blown piston.
Maybe the lower lost a gear.J

 

[baylinerboater1]

Re: Force 50hp idles Loud (knocking)

Question - does your motor run rough on idle, once you get it going? Mine shakes a bit, jerks the steering wheel a bit. But, once in gear and above 1000 RPM or so, it runs great. Any carb trick or something you know of? I have new plugs in (runs the same as the old plugs..) Thanks. 1990 Force 50 HP.

 

[tater76]

Re: Force 50hp idles Loud (knocking)

Sorry, but Jerry is right about the crank or cylinders. Pull the head to inspect the cylinders, I know it seems very daunting of a task to some. However, it is very simple process to unbolt all the bolts, and it comes right off. Tell us what you find in there. I bought a 50 a few months ago with a broken crank. It would idle, and rev up to a point where it would "knock". I cracked the case, and sure enough the crank was split.

 

[barnaldo]

Re: Force 50hp idles Loud (knocking)

My Force 120 started doing the same thing, replaced reed valves, and diaphragm fuel pump. Runs smooth and quiet.