Maycraft with a mercury falling on its face!!

[Blowin Time]

Good afternoon gentlemen. I am a proud owner of a 2002 May craft 1900cc with a 2002 model Mercury 125 saltwater edition 2 stroke. Not my favorite engine but actually performs very well. I bought the boat in January 2012. 10 lake trips before taking it 4 weeks ago to the ocean. 5-7 ft seas for 8+ hours, not a nice day to be on a 19' vessel. The next day just running across the bay it acted like it was slightly starving for fuel for about 10 seconds then cleared up. My next outing in the the lake it did it again for 20 seconds with a little more intensity. This past weekend it did it a little on Saturday but on Sunday (memorial weekend) the lake was super choppy with boat wake. I was running 25mph in 3' wake and every time I hit a good one the motor dropped momentarily back to idle then back to 4000rpms. I reached a no wake zone so I returned to idle. Upon throttle up it planed out then starved for fuel all the way back to 5mph and would hardly go. I returned it to idle, I powered up again and as soon as it got on plane it did it again. This went on for 5 miles. I returned to dock. Changed the filter in the motor and the external fuel/water separator and test drove. No change. The next day I ran it for 4 miles before putting it on the trailer with no problems. What the heck is going on???? Please help, I don't want to get stranded!!

 

[CharlieB]

Re: Maycraft with a mercury falling on its face!!

Check fuel flow after the low pressure fuel pump. Disconnect the hose point into a suitable container crank the motor and watch for a nice strong fat pulsed fuel flow. Any weakness is cause for suspicion and inspection of the pump, hoses, fittings, and the pick-up tube in the tank. If you pull the fuel tank fitting, drop a small weighted hose to the bottom of the tank and siphon off a sample to check for water accumulation as over time you can get a bit which with waves can get picked up and overload the filters and cause problems.

 

[Blowin Time]

Re: Maycraft with a mercury falling on its face!!

I did that with a nice flow. However, the fact that the problem was intermittant was a cause for concern. I dug deeper to find some strange material in the engine debris filter. Upon further investigation, found the line between the fuel/water separator and the engine was a grey line that came with a quicksilver kit that added the separator to the boat that didn't originally come equipped with one. Over the years of ethanol fuel use had deteriorated the inner liner of said hose. This once plastic liner now became floating debris which blocked fuel flow as it piled up at hose barb connections and half filled brand new filter element. Replaced line from tank to engine, installed glass filter on engine to monitor debris buildup, and test drove boat for 4 hours. All is well and power was restored. Thanks for your post.