Mercury outboard 4st problem

[sporty1]

Hi guys

hopefully someone can offer some advice to mate who is having major problems with his outboard and getting no answers from various outboard mechanics.
the motor is a 60hp Mercury 4stroke unsure of the year but will find out.

the motor first up was showing signs of missing at about 6 knots but was fine the rest of the time.

he was told it could be a spark plug problem and that as the plugs carbon up a bit it causes interference with misfiring.

it continued and the coils were replaced and then the problem started to become more severe.

to the point where it now intermittently will run perfectly for a time and then only run at 6 knots and no faster.

He he has also had the map? replaced and has now been told it could be a computer problem?

i will endeavour to get more info but apart from the expense the unreliable outboard is causing him much grief.

[Mike Delisser]

I have the same motor, and I've had a couple of issues but not that one.
Where are you having the work done?

[docaster]

I would get the injectors cleaned.

[shappy]

hey mate, i had a 60hp suzuki that had a similar problem that you are describing and turned out to be fuel.drained and cleaned tank and problem was fixed

[Spaniard_King]

Your symptoms are familiar
The merc 60 has always had issues with the water tube grommet growing, shutting off the water supply to the power head.
The only rectification /repair is to remove the power head and replace the grommet. Sorry but it is what it is!

[kizza1]

wont be watertube grommet if its doing it at 6knots. water tube grommet restricts flow not pressure and would put engine in limp mode while vessel is on the plan in higher rev range.
would help if we knew if it was an early yammy powerhead, or later merc efi.

[sporty1]

Hi guys thanks for the replies so far. I will have some more info later today.