engine skips a beat

[Mutt020]

Quick one here...when I get the engine started and warming up, about every 5-10 seconds you can hear it miss. The best way I can describe it is that it "skips a beat". It'll keep running, but it'll jump. Every once and a while this will cause the engine to die when idling.

Ideas? I recently just changed all the plugs. I noticed that one of the plug wires had its end cap missing, and it had the metal wire end simply wrapped around the spark plug. It was wrapped tightly, so I'm sure it was connecting, but could this be a culprit?

Does anything else cause the engine to miss, or skip a beat?

Thanks.

 

[F_R]

Re: engine skips a beat

Coughing/sneezing/skipping at idle is usually a sign of running too lean. What motor is it and does it have an idle mixture control? Tweak it a bit toward rich and see what happens.

 

[Mutt020]

Re: engine skips a beat

engine is an outboard evinrude, 200hp 6 cyl. Theres no lean/rich adjustment on the carbs...and they were just cleaned. There is an idle adjustment (just a screw) on the engine, but I think this just moves the throttle position forward or backwards...maybe not? I haven't played w/ the idle speed yet.

So, the plug wires wouldn't have any play in the skipping?
I'm just looking for any and all possibilities for the small problem. Thanks.

 

[F_R]

Re: engine skips a beat

OK, knowing what motor you have might change the answer I gave. Sure, plug wires could cause an electrical missfire. Really it comes down to whether it is an electrical missfire or lean condition sneeze. That's a real hard one to diagnose without actually hearing it.

 

[Mutt020]

Re: engine skips a beat

thanks for your replies. Anyone know how the idle speed adjustment works on these types of engines. Again its a 2-stroke 200hp 6cyl, year 1986 evinrude. I'm just curious whether the idle speed adjustment actually fluctuates the fuel, or whether it simply moves the throttle position back and forward.

 

[F_R]

Re: engine skips a beat

Idle speed adjustment merely limits how far you can move the throttle toward idle.

While on a related linkage subject, if a carburetor throttle butterfy is not closing completely at idle, it will cause a lean condition on that carb, and sneezing.

 

[Kevin W]

Re: engine skips a beat

Is the engine warm when it is skipping?
If the engine is still cold or not fully warmed up a lean skipping is not uncommon.
basically all engines need a little more fuel to warm up.

if it is already warmed up a lean condition could exist.

 

[ezeke]

Re: engine skips a beat

I believe that all of your jets are fixed. Your concern will be that the linkage is set so that the throttle plates are synchronized. I think everyone agrees that you have a lean condition, just not what is causing it.

You may want to check that your pulse limiter has been updated to the blue and gold one, and that it is clean. Also check that all of your fuel lines are tight. Any air leak in the system can cause your condition, including the carburetor gaskets.