LEIGH MIDDLETON
Active Member
Here is the previous message.
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Motor acting up by Leigh-Beaux, 10/3/2011 11:08 ET
Category - Motors
90 HP ELPTO 2 stroke 2004 Merc Tracker.
Dang think is acting silly and wont perform better than 30 MPH or 4000 RPM unless brother in law is in back pumping the bulb. Then it hits what I think is normal (47 MPH @ 5500 RPMs). We have changed fuel lines w/bulb, spark plugs, fuel pump rebuild kit, and the only thing we can think of now is man up and buy a brand new fuel pump??? Any suggestions at all would be great. Also, what should a 2004 NX750 w/90HP ELPTO 2 stroke run at??? New 1st time boat owner and all I know when I test drove it a month ago we ran 47 mph @ 5500 RPM. Thats why I am expecting this performance. Please help.
re: Motor acting up by Bob B.,10/3/2011 12:34 ET
Couple of things might be going on. The most crucial "test" you performed is pumping the primer bulb, and getting the performance back to "normal". By doing this, you have proven that the electrical system is functioning properly, the motor has compression, and it is basically being deprived of the PROPER amount of fuel.
Yes, those peak numbers sound right....
-1] Perform compression check. Even though I think we're ok, start here. Diaphram pumps are pulsed off base compression. You can have a good TOTAL peak PSI number, but if base compression is weak, pulse pumps cannot do their job.
-2] Fuel sample. Be sure there is no water.
-3] Rebuild pump again. My bet is herein lies the problem.
-4] By pumping the bulb, you may be actually overpowering the carb needles, pushing fuel through, giving the motor what it needs. In this case, carbs need to come down and be cleaned. Be sure to check float height and perform a proper synchronization.
Certified Merc Service Manager ......cut me and I bleed BLACK.
10-10-11
OK, update now is the fuel pump is reworked and it is still doing it but I`m now at 40 MPH and 4500-4700 RPM`s but I cant run down the lake at full throttle for more then 30 seconds. I just dont know why after 30 seconds of full throttle it starts missing and acting up. I feel like it could be bad gas but dont know how to check it. I feel like it could be in the 3 carbs or some float issue but IDK how to check any of that stuff. I`m not afraid to dig into it if I just knew what to do. Also, can you tell me what the solonoid does and where the fuel goes from there? I just dont know where to go from here and would kick and scratch to keep it from going to the shop.
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Motor acting up by Leigh-Beaux, 10/3/2011 11:08 ET
Category - Motors
90 HP ELPTO 2 stroke 2004 Merc Tracker.
Dang think is acting silly and wont perform better than 30 MPH or 4000 RPM unless brother in law is in back pumping the bulb. Then it hits what I think is normal (47 MPH @ 5500 RPMs). We have changed fuel lines w/bulb, spark plugs, fuel pump rebuild kit, and the only thing we can think of now is man up and buy a brand new fuel pump??? Any suggestions at all would be great. Also, what should a 2004 NX750 w/90HP ELPTO 2 stroke run at??? New 1st time boat owner and all I know when I test drove it a month ago we ran 47 mph @ 5500 RPM. Thats why I am expecting this performance. Please help.
re: Motor acting up by Bob B.,10/3/2011 12:34 ET
Couple of things might be going on. The most crucial "test" you performed is pumping the primer bulb, and getting the performance back to "normal". By doing this, you have proven that the electrical system is functioning properly, the motor has compression, and it is basically being deprived of the PROPER amount of fuel.
Yes, those peak numbers sound right....
-1] Perform compression check. Even though I think we're ok, start here. Diaphram pumps are pulsed off base compression. You can have a good TOTAL peak PSI number, but if base compression is weak, pulse pumps cannot do their job.
-2] Fuel sample. Be sure there is no water.
-3] Rebuild pump again. My bet is herein lies the problem.
-4] By pumping the bulb, you may be actually overpowering the carb needles, pushing fuel through, giving the motor what it needs. In this case, carbs need to come down and be cleaned. Be sure to check float height and perform a proper synchronization.
Certified Merc Service Manager ......cut me and I bleed BLACK.
10-10-11
OK, update now is the fuel pump is reworked and it is still doing it but I`m now at 40 MPH and 4500-4700 RPM`s but I cant run down the lake at full throttle for more then 30 seconds. I just dont know why after 30 seconds of full throttle it starts missing and acting up. I feel like it could be bad gas but dont know how to check it. I feel like it could be in the 3 carbs or some float issue but IDK how to check any of that stuff. I`m not afraid to dig into it if I just knew what to do. Also, can you tell me what the solonoid does and where the fuel goes from there? I just dont know where to go from here and would kick and scratch to keep it from going to the shop.
