I have a 2002, 2 stroke 90hp Merc that I have been using to troll at low RPMs for 4-8 hours an outing. I just got into trolling this season and am trying to figure out if what I am experiencing is related to low RPM operation.
Does several hours of low RPM operation have a tendency to allow unburt fuel and oil to build up in your exhaust system and seek its way out through your exhaust and cooling system in the form of a yellow oily substance?
I have noticed an yellow substance biuld up at the 3 hole exhaust port at the back of the engine. The build up of the substance typically got washed away by the waves when I came to a stop. A week ago I noticed a small puddle on the garage floor and I traced it to a water port located on the lower unit next to the oil level screw.
I took the boat into the shop and they replaced the impeller, seals, gaskets, plastic sleeve for the propeller shaft, pressure tested the lower unit, new plugs, tuned the carbs, and adjusted the linkage. They told me there was a little water in the lower unit and everything is good now.
Saturday I trolled with the boat for the first time since picking the boat up from the shop, put the boat away, and the next day I have a small puddle of oil on the floor again. It was coming out of the same water port at the oil level screw. I wiped everything down and took the boat out to troll yesterday. I told myself that it was residual from the repair and slow trolling the previos day did not allow the substance to get blown out. The motor was hard to start and stalled out several times, but it was a cold morning (45 degrees) so I thought it was normal. I trolled for 4 hours. I was 5 miles from the launch so when I was done I was able to open her up and let her scream a bit.
I checked the motor and the floor this morning and at lunchtime and the water port is not oozing anyting. All is dry and clean.
Assuming the lower unit is sealed, is there any other reason I should experience this yellow oily discharge? Should I drain the lower unit to confirm there isn't any water in it and the shop didn't screw that up?
Thanks for your help.
Matt
Does several hours of low RPM operation have a tendency to allow unburt fuel and oil to build up in your exhaust system and seek its way out through your exhaust and cooling system in the form of a yellow oily substance?
I have noticed an yellow substance biuld up at the 3 hole exhaust port at the back of the engine. The build up of the substance typically got washed away by the waves when I came to a stop. A week ago I noticed a small puddle on the garage floor and I traced it to a water port located on the lower unit next to the oil level screw.
I took the boat into the shop and they replaced the impeller, seals, gaskets, plastic sleeve for the propeller shaft, pressure tested the lower unit, new plugs, tuned the carbs, and adjusted the linkage. They told me there was a little water in the lower unit and everything is good now.
Saturday I trolled with the boat for the first time since picking the boat up from the shop, put the boat away, and the next day I have a small puddle of oil on the floor again. It was coming out of the same water port at the oil level screw. I wiped everything down and took the boat out to troll yesterday. I told myself that it was residual from the repair and slow trolling the previos day did not allow the substance to get blown out. The motor was hard to start and stalled out several times, but it was a cold morning (45 degrees) so I thought it was normal. I trolled for 4 hours. I was 5 miles from the launch so when I was done I was able to open her up and let her scream a bit.
I checked the motor and the floor this morning and at lunchtime and the water port is not oozing anyting. All is dry and clean.
Assuming the lower unit is sealed, is there any other reason I should experience this yellow oily discharge? Should I drain the lower unit to confirm there isn't any water in it and the shop didn't screw that up?
Thanks for your help.
Matt