The Mercury Mystery

[jimbo 69]

I recently went on an ill fated fishing trip with one of my mates who has a 2006 model 140HP Mercury 2 stroke with only 44 hrs pod mounted to the back of an old Savage Bluefin. After a tip top day of trouble free boating we were heading back to the marina when the motor suddenly died a couple of miles out. Thinking we must have run out of fuel, we quickly changed over to the reserve tank and managed to get the motor running again. After another brief period it stopped again and this time failed to start and after several attempts also failed to turn over. Anyway to cut a long story short we got the boat home thanks to our great mates the Coast Gaurd and proceeded to inpect the engine further. The starter cables looked burnt so we tried to turn it over by hand but to no avail. After removing the spark plugs, No 4 cylinder plug was found to have molten aluminium hanging off the end of it. The oil injection tanks were both full and there was no obvious reasons as to why it would have happened. It's booked in to the Mercury mob in a few days time to see if they will honour the Warranty, I was wondering if anyone was aware of known problems with these motors, especially the oil injection system as it is almost certain that it leaned out in No. 4 pot only. Also has anyone dealt with Mercury on a warranty basis before.
Any advice would be greatly appreciated!!!
Cheers,
Jimbo.

[Blackened]

G'day

No Idea but doesn't seem good. Have dealt with merc before regards warranty, brilliant would be the best word to describe them

Dave

[Noelm]

no real known problems, but as the old saying goes "sh!t happens" hopefully it will be covered by warranty, and an Oil system failure would more than likely result in all or at least most of the Cylinders being toasted (maybe) was there any alarm? Most Warranty claims will need to have the Dealer onside right from the start, I hope they are reputable!

[FNQCairns]

Bugger! You will need a lot of luck under warranty to come out of this cheaply.

2 standout reasons and unfortunately neither is warrantable, 1 is old fuel (4 weeks even)and 2 is a lean condition in the carb that supplies that cylinder. Also a combo of the above 2 can cause an unexpected surprise!

It's hard to hear on the water when 1 cylinder is going bad in a 4cyl engine and I think your engine has 1 carb for each, not sure though.

In a generic sense, Crank sensors can do it as can poorly set timing or a mechanical carb failure also specific cdi probs so there are warrantable options, dunno what may apply to your engine though.

Best of luck

cheers fnq

[20vwestie]

Hi,

Piston meltdown points to incorrect mixture in that cylinder, quite possible if the engine is of the carburettor variety with one carby per cylinder. Incorrect ignition timing will have the same effect but would have damaged all four pistons. This may be the case, with only No 4 cylinder showing evidence. Only a strip down of the engine will tell.

Cheers

Rob

[jimbo 69]

She's a V6 version and looks like 3x carbs feeding 2 cylinders each. None of the other plugs showed any sign of damage or burning that would indicate leaning out. Doesn't make much sense as the opposing cylinder running on the same carb should also have leaned out. There were no alarms activated and the temp gauge was sitting between half and 3/4 which is quite normal. Guess he'll just have to let the Merc guys strip it down and nut it out.

[Noelm]

yep, that seems like what will happen, but be sure they find out what caused the failure, otherwise it will surely occur again, and this time it may be 20 miles from shore or even worse 20 miles from shore when it is as windy as buggery and raining and dark as well (murphies law you know)

[Spaniard_King]

Most Warranty claims will need to have the Dealer onside right from the start, I hope they are reputable!

Noelm is on the money, he is more likely to gain warranty if he has a repore with the dealer. Hard to swallow sometimes but it could swing either way on the dealers word

[Noelm]

yep, I have seen this before, sometimes a claim will be entirely at the Dealers discretion and knowledge after inspection, so lets hope for the best, and keep us posted.

[FNQCairns]

Yeah good luck, worth a lot of "but I don't understand how one can go and the other pot still looks perfect, shouldn't they both show evidence of melting some melting but one happend to go first??????" even the most experienced mechanic will have trouble convincing a skeptic of a reason on any individual engine, then follow with " so could it have been a bad piston or cooling circulation around this cylinder?".....

anyway good luck, worth checking on spark timing as it pertains to that cylinder and ONLY that cylinder.

cheers fnq