B-Reynolds
Cadet
- Joined
- May 25, 2009
- Messages
- 10
I recently purchased a pontoon boat with a 2002 mercury 90 elpto 2-stroke.
The motor has a knock and rough vibration (Grinding rattle vibration) when in gear at a low idle speed and when out of gear in neutral . I recently took the boat to a tech. and he said he adjusted the timing cleaned carbs and tuned them. Changed lower unit oil. (found no metal shavings) I checked compression it was 110,110,110. New spark plugs. (old ones were Black around ceramic in some areas and wet with black oily gas.)
The tech was able to get the motor smooth when in neutral but when in forward gear at no wake speed the problem remains.
On the water played with the idle mixture screws and noticed that the noise got very rough and came back when in neutral when rich. (Grinding rattle vibration not a putter). then got better when leaned out.
I have attached a picture of the carb synchronization marks. The manual shows these marks lined up parallel to the ground during adjustment (is this with the boat in nutral?) and then slightly up at the end(it states nutral here). My marks only line up when the boat is in gear and throttle slightly forward. Is this normal?
I was also looking at the timing pictures in the manual and the markings are not the same. Am I looking in the wrong place? I want to check the timing myself and im not sure where all the markings are and i dont want to take stuff apart looking blindly for them?
How do i check if all cylinders are firing right? i did notice that when plug 2 is removed that the motor hardly changes how it is running. (It took me a while to notice any change). The other two change performance clearly.
the picture of the tic marks is what is seen with time light when in neutral idle 800 rpm
Im a new guy to boating and am looking for any ideas. Thanks
The motor has a knock and rough vibration (Grinding rattle vibration) when in gear at a low idle speed and when out of gear in neutral . I recently took the boat to a tech. and he said he adjusted the timing cleaned carbs and tuned them. Changed lower unit oil. (found no metal shavings) I checked compression it was 110,110,110. New spark plugs. (old ones were Black around ceramic in some areas and wet with black oily gas.)
The tech was able to get the motor smooth when in neutral but when in forward gear at no wake speed the problem remains.
On the water played with the idle mixture screws and noticed that the noise got very rough and came back when in neutral when rich. (Grinding rattle vibration not a putter). then got better when leaned out.
I have attached a picture of the carb synchronization marks. The manual shows these marks lined up parallel to the ground during adjustment (is this with the boat in nutral?) and then slightly up at the end(it states nutral here). My marks only line up when the boat is in gear and throttle slightly forward. Is this normal?
I was also looking at the timing pictures in the manual and the markings are not the same. Am I looking in the wrong place? I want to check the timing myself and im not sure where all the markings are and i dont want to take stuff apart looking blindly for them?
How do i check if all cylinders are firing right? i did notice that when plug 2 is removed that the motor hardly changes how it is running. (It took me a while to notice any change). The other two change performance clearly.
the picture of the tic marks is what is seen with time light when in neutral idle 800 rpm
Im a new guy to boating and am looking for any ideas. Thanks
