PDA

View Full Version : Fumes from Outboard



Angla
18-08-2005, 08:01 AM
Has anyone else had any problems with fumes from their motor.
I have a half cabin and the 135 Optimax has been great from when it was new 18 months ago and then about 2 months ago started getting fume smells while cruising. Speed did not change the odours at all.
I figured I would wait until the 100 hour service and they could find the problem. No clues there but they did say the plugs were fairly dirty. Asked me what fuel and I said always BP Ultimate 98 octane. Oil was always only Mercury optimax oil so no point looking at this.
They checked the manual and said only 87 octane was recommended. So added 80 litres of unleaded 92 to the 80 litres left in the tank and now the fumes seem to be gone. Figure on only using normal unleaded from now on.
Funny how I did not have a problem for so long until now. Maybe there is a new additive in the fuel. Anyway it seems I have just wasted good money for nothing on the more expensive fuel.
It seems just a good thing to have done for the performance of the motor but really was bad it seems.
Performance has not appeared to have changed and I do and have always found good economy from the motor, around 1 litre or a little less for 1 knott (Generally 19-21 litres per hour for 21-23 knotts, 26-27 for 26 knotts, 41 for 38 knotts full speed)

Angla

Oldyella
18-08-2005, 08:13 AM
Did you add any front wind sheilds or side curtains lately ? Outboard fumes (I love em :o) tend to get dragged back into the cabin when you have all the canopy and sides closed. This causes a "slipstream" effect. Try opening a few and see if it changes. 87 octane is OK for Mercs, unless a high performance racing motor.

Angla
18-08-2005, 09:52 AM
RD, Always have had the canopy and even with the sides and front out it still gave an odour. You must remember that It never gave this problem for the first 15 Months.
My post was more meant to inform people, not to look for a solution as that has been found I believe.

Angla

scuttlebutt
18-08-2005, 11:57 AM
Hey guys, just a bit confused about the octane rating. Is 87 right? I might be a dumbass but I was of the belief that standard unleaded is rated 91 octane, premium at 95/96 and "ultimate" and "optimax" at 98. Or does the 87 part relate to a different scale?

cheers,

steve

Sportfish_5
18-08-2005, 12:01 PM
Sorry to go off-topic Angla but did you buy that cover for your transducer or was it factory fit out ? Looks better than the one I had bought.

Cheers

Greg

Gbanger
18-08-2005, 12:27 PM
scuttlebutt i think 87 is the standard ron rating for standard US petrol.

remember that from somewhere