mercury 120 internal jet (Hard starting)

[B_Eager]

ran fine first three years from new. 4th year boat started hard after warm. last year had a 1,000$ put into boat at the dealer. boat still starts like crap when warm. Starts fine when cold. Latest suggestion is to run hotter plugs, any thought on this. By the way mercury is no help, there suggestion is take to a different dealer and pay another 1,000$.

 

[rodbolt]

Re: mercury 120 internal jet (Hard starting)

may be time for a carb cleaning, fuelpump rebuild and general diagnostics to include a cleaning of the puddle drains. changing plugs wont help and may hurt. the 90 and 120 sport jets were notorious to eat reeds. especially if the impeller to wear ring clearence is not in spec. check the reeds carefully with a flashlight with the carbs off. look at the tips of them.

 

[B_Eager]

Re: mercury 120 internal jet (Hard starting)

Had the boat in for 6 weeks last year and they were unable to fix, dealer pulled the carbs cleaned, checked the return lines, replaced the stator (don't believe that was bad, but it checked out bad by them. Did a full diagnostics on the boat. That is why I am here. They went down as far as the reeds, but not sure if the checked them.<br />The prop clearance, what does that have to do with it, no cavitation. Can you explain a little.<br />Have the mercury service manual, am mechanicaly inclined, how hard is it to get to the reeds, or should I go with the dealer?

 

[rodbolt]

Re: mercury 120 internal jet (Hard starting)

remove the carbs and the intake and your looking at them. the impeller to wear ring clearence is a maint check. if it becomes to large the engine speed willincrease placing a larger load on the reeds. usually idle quality and top end suffer as well from a chipped reed.<br /> last one I did had chipped 4 reeds. I am with merc, may be time for a dealer with techs that have diagnostic skills.

 

[KennebecRiverGuide]

Re: mercury 120 internal jet (Hard starting)

If the impeller to wear ring clearence is out of spec water will force by the outside edges of the <br />impeller, which will result in higher RPM's because of the decreased load. This can lead to overreving beyond the allowable WOT R.P.M. spec. Your hole shot<br />(such as it is with a jet) may decrease drastically.