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Seaman
- Joined
- Oct 21, 2006
- Messages
- 50
Equipment: 1999 Mercury ELPTO 90hp (with 96 hours on the unit). Ranger R61 (though that information prob doesn't matter).
Ok.....so I realize that there seem to be a million threads on this topic.....and if feels like I have read them all. I can't seem to make any headway and I am REALLY frustrated.
So I will try to describe what is going on and....with as much detail as possible....what I have done to try to correct it.
When the boat is working (and it does intermittently) I can hit about 5300 RPM and 41 MPH at WOT, which is almost dead on for the boat and prop pitch.
Problems/Symptoms: (all seem to be related but manifest themselves at different times not all at once)
1. On some hole shots its often VERY sluggish and will only make about 2200 to 2500RPM, sometimes with surges....sometime not.
2. On other hole shots it will sometimes jump to life like its gonna go, but will only hit about 3000 RPM and then back down to about 2200 RPM and stay there at WOT..
3. If I can push it past that first problem (or it doesn't appear) I will only get about 4000 RPM at WOT and obviously a lot less speed. Sometimes that is constant (it just maxes out that way) and sometimes it will surge up to about 5000 RPM in quick kicks but not stay there.
Here is a list of things I have tried to cure/diagnose the problem.
- Changed plugs (twice....before and after a decarb) using the factory specified NGK plugs
- Changed fuel filter
- Changed the fuel/water filter AND the housing for it.
- Replaced all fuel lines back to the fuel/water filter and checked the connections (using double clamps at each fitting). Didn't go back to the tank because its under the seats and a pain to get to, but I don't think this is the issue as I will explain later.
-- Replaced fuel bulb with a mercury bulb (after being told by someone that my first Bass Pro replacement wasn't good enough)
-- Replaced the hose quick connect at engine cowling.
-- REBUILT THE FUEL PUMP with a Mercury kit.
-- Decarbed the engine using sea foam and the method described by most posts.
-- Did a compression test on all three cylinders (each reading at about 135).
-- Did a fuel system test as described by Capt. Jason and Don in the FAQ forum. (Did the test before rebuilding fuel pump). No bubbles.......gauge read pretty much 0 inches of mercury when running.......on pump test it held at least 5 inches or more. So no positive findings there.
-- I totally detached the fuel lines and connected a one gallon gas tank on a one foot hose direct to the merc quick connect....same problem. (which is why I don't think it has anything to do with the boat side of the fuel system).
-- removed the carb cover and sprayed down everything really well with both deep creep and carb cleaner to make sure nothing was stuck or clogged.
-- I even TEMPORARILY removed the fuel filter and connected the carb direct from the fuel pump to see if that was the source.
-- Double checked and reseated the spark plug wires.
-- (Tomorrow I will likely get new wires and maybe coils just to make sure that isn't the issue.)
Ok......so there you have it.....hopefully that is enough detail to get SOMEONE some idea what the heck might be wrong. This engine only has 96 hours on it and DOES run correctly when I can get to. But the last few days its been happening more and more.
(oh.....one note.....not sure if this helps or is just common sense......but on one of the tries with the carb cover off running at about half throttle.....I sprayed some deep creep into the carb and it picked right up. That's prob common sense....but I thought I would relay it in case it offers some diagnostic help that the system isn't getting enough gas).
PLEASE HELP!!!!
I am sure some is gonna tell me that I need to rebuild the carbs. If the is the solution so be it.....but it seems like its something else.....especially since I CAN get it to run properly at times at WOT.
Ok.....so I realize that there seem to be a million threads on this topic.....and if feels like I have read them all. I can't seem to make any headway and I am REALLY frustrated.
So I will try to describe what is going on and....with as much detail as possible....what I have done to try to correct it.
When the boat is working (and it does intermittently) I can hit about 5300 RPM and 41 MPH at WOT, which is almost dead on for the boat and prop pitch.
Problems/Symptoms: (all seem to be related but manifest themselves at different times not all at once)
1. On some hole shots its often VERY sluggish and will only make about 2200 to 2500RPM, sometimes with surges....sometime not.
2. On other hole shots it will sometimes jump to life like its gonna go, but will only hit about 3000 RPM and then back down to about 2200 RPM and stay there at WOT..
3. If I can push it past that first problem (or it doesn't appear) I will only get about 4000 RPM at WOT and obviously a lot less speed. Sometimes that is constant (it just maxes out that way) and sometimes it will surge up to about 5000 RPM in quick kicks but not stay there.
Here is a list of things I have tried to cure/diagnose the problem.
- Changed plugs (twice....before and after a decarb) using the factory specified NGK plugs
- Changed fuel filter
- Changed the fuel/water filter AND the housing for it.
- Replaced all fuel lines back to the fuel/water filter and checked the connections (using double clamps at each fitting). Didn't go back to the tank because its under the seats and a pain to get to, but I don't think this is the issue as I will explain later.
-- Replaced fuel bulb with a mercury bulb (after being told by someone that my first Bass Pro replacement wasn't good enough)
-- Replaced the hose quick connect at engine cowling.
-- REBUILT THE FUEL PUMP with a Mercury kit.
-- Decarbed the engine using sea foam and the method described by most posts.
-- Did a compression test on all three cylinders (each reading at about 135).
-- Did a fuel system test as described by Capt. Jason and Don in the FAQ forum. (Did the test before rebuilding fuel pump). No bubbles.......gauge read pretty much 0 inches of mercury when running.......on pump test it held at least 5 inches or more. So no positive findings there.
-- I totally detached the fuel lines and connected a one gallon gas tank on a one foot hose direct to the merc quick connect....same problem. (which is why I don't think it has anything to do with the boat side of the fuel system).
-- removed the carb cover and sprayed down everything really well with both deep creep and carb cleaner to make sure nothing was stuck or clogged.
-- I even TEMPORARILY removed the fuel filter and connected the carb direct from the fuel pump to see if that was the source.
-- Double checked and reseated the spark plug wires.
-- (Tomorrow I will likely get new wires and maybe coils just to make sure that isn't the issue.)
Ok......so there you have it.....hopefully that is enough detail to get SOMEONE some idea what the heck might be wrong. This engine only has 96 hours on it and DOES run correctly when I can get to. But the last few days its been happening more and more.
(oh.....one note.....not sure if this helps or is just common sense......but on one of the tries with the carb cover off running at about half throttle.....I sprayed some deep creep into the carb and it picked right up. That's prob common sense....but I thought I would relay it in case it offers some diagnostic help that the system isn't getting enough gas).
PLEASE HELP!!!!
I am sure some is gonna tell me that I need to rebuild the carbs. If the is the solution so be it.....but it seems like its something else.....especially since I CAN get it to run properly at times at WOT.
