help losing cylender at high rpms

[tmonaco2]

I HAVE A 1988 EVENRUDE 140 .. I HAVE GOOD SPARK AT IDLE AND WHEN I INCRESE RPM'S AND SPEED ,CYLENDER STOPS FIRING AT ABOUT 1500 RPM'S I HAVE GOOD SPARK AND 125 POUNDS OF COMPRESSION. I HAVE ALREADY CHANGED COILS SPARK PLUG AND CHECKED CARB ,ALSO CYLENDER WILL INTERMITENTLY FIRE OFF AND THEN CUT OUTWHEN PROBLEM FIRST STARTED ... NOW IT WON'T EVEN DO THAT. I WOULD APPRICIATE ANY SUGGESTIONS OR ANYONE WHO HAS HAD ANY SIMILAR PROBLEMS I HAVE EXHAUSTED ALL MY KNOWLEDGE , I NEED SOME HELP.<br />I ALSO CHECKED PLUG FOR WATER AND FOUND NONE.I AM A MECHANIC FOR CARS AND COULD ALWAYS FIX MY BOATS THIS IS DRIVING ME CRAZY THAT I CAN'T FIGURE IT OUT ANY HINTS WOULD BE APPRICIATED <br /> THANK YOU<br />TONY

 

[fireman57]

Re: help losing cylender at high rpms

Welcome to iboats but please don't shout at us (with caps). If you have a powerpack on this engine it may be going south. Check all your connections and grounds. Clean them all. Can you swap coils on your engine and see if this problem follows? You need to get a OEM manual. It will save you a lot of headaches, time, and money.

 

[Walker]

Re: help losing cylender at high rpms

You aren't making any sense here. You have to be more specific. You say cylender stops firing at 1500rpm's I have good spark. <br />If you have compression and spark, then you have a fuel problem. Clean the carbs good.