2006 Mercury 50 EFI has lost power

[piikki]

Hi,

My 2006 Mercury 50 EFi Four stroke lost power and also idle it sounds quite rough, I would guess that it runs only with three cylinder.

Normally it has easility run about 5500 -5700 rpm but now only about 4000 is max. When turning on it beeps normally, so from diagnostic point of view no issues detected. In run time no warning beeps just lost power, poor acceleration and max.speed.

So far fuel filter/water separator cleaned and thermostat checked. Also gasoline changed but no helped. Tomorrow I will take it to trailer and change spark plugs. Has any one faced similar problems and help me to find solution ?

And any hint how to change spark plugs "easily". I have once done it and it was not easy job so all hints are welcome, can it be done without removing ingantion couil plate and lower cow?

t. JR

 

[Montauk72]

Re: 2006 Mercury 50 EFI has lost power

I had the same exact thing happen to my 2008 40 hp EFI 2 years in a row. Unfortunately I think I am starting to experience the same problem intermittently with my 2008 90 EFI now. It was one of the three coil packs each time that caused similar symptoms you describe. Thankfully they were covered under warranty. It sounded fine at idle but once it was put in gear it ran rough and could barely get above 10mph. Good luck

 

[pihlaja]

Re: 2006 Mercury 50 EFI has lost power

Hello, I had exactly same symptoms, engine ran only with 3 cylinders. Reason was quite strange, 2 uppermost fixing bolts of the rocker shaft had become loose, obviously they had been like that from factory (china). The rocker shaft broke suddenly at about 5000 rpm, causing valves of 1st cylinder to stay nearly closed. Luckily there was nothing else broken, and i got the part from salvage yard for 40 ? (about 50$). Here in Finland a new part would be about 300$ and delivery time weeks.
Changing the spark plugs without removing the coil plate may cause broken plug (happened to me) or even worse, damaged threads. Removing the coil plate is easy compared to those.
w.g.
Ilpo