Miss when first started...25 h.p. Merc

[ehenry]

My 1999 model 1-02530wd 25 horse Merc has on odd problem. It Cranks very easily, runs great at all ends of the throttle range. The problem is after you start it and let it warm up for a few minutes, no matter how long, it will miss for a few seconds when you apply the throttle to it. Other than that there are no problems with it. Any idea's. Everything is fresh...plugs, gas, the whole nine yards. It only does this on the first crank of the day.

 

[ehenry]

Re: Miss when first started...25 h.p. Merc

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[ehenry]

Re: Miss when first started...25 h.p. Merc

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[FlyBoyMark]

Re: Miss when first started...25 h.p. Merc

Low speed idle jets out of adjustment or dirty, plugs could be wrong heat or slightly fouled. Put a strong dose of Mercury "Fuel System Cleaner" in the next tank of gas, check carbs for gunk. This is a symptom of not enough gas or fuel in the lean idle condition. As a last thought, carbon deposits in combustuion chamber could be causing detonation when the little bits glow and get hot. Try Mercury "Power Tune" spray in the engine using half the can first round. Spray till engine loads up and almost quits, repeat till almost half can is used then load up with steady spray till enigine quits, set for 20 minutes. Then repeat on last half of can. Proccess will take about 1 hour at least. This removes all carbon and degunks the engine internaly. Might want to check the engine running at nite in total darkness with the cover off and look for spark leaks.