boat motor trouble

[PWE21]

Some times when I take off my mercury motor boggs you may go 30 feet or a half a mile then it takes off. If any body has a idea whats wrong please let me know.

 

[yellburt]

<font color="#3300cc"><font size="3"><font face="comic sans ms,sand">i had a 70 evirude that did the same thing an it was the carbs, dirty. emoUSA
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[wrechin2]

Need more info on the engine. It could be in the carb or carbs which ever the case may be or it could be electrical. Have you tried pressing the key in when it boggs to see if it picks up?

 

[Crizzel]

I agree more info in needed on what merc your running.. I would suggest changing out your fuel line from the bulb to engine along with the primer bulb first though. Ethanol is hell on the gas lines.

 

[lurch154]

If it is an optimax check the low pressure fuel pump. Had similar problem. That's what it turned out to be.

 

[PWE21]

200 EFI and I have changed the fuel line and the bulb.and put new power packs on it

 

[Fisherman550]

I had a 70 Johnson that did the same thing-turned out to be the fuel.

 

[wrechin2]

Now that we know what engine.... It could be the low side of the stator, stopped up bleeder valve, ECU (computer), fuel pressure (electric fuel pump), bad fuel, ect. These are some of the tings that I have found on a EFI engine that has caused your concern. Does it miss badly when it boggs? How often does it do it?

 

[PWE21]

it dont miss it just boggs on take off it sounds like it is running on three cylinders you can tell when its is going to do it when you crank it up . it seems to be doing it more and longer as time goes by.

 

[wrechin2]

Sound like it may have the low side of the stator going out. It can actually be running on 3 cylinders if it is going bad. I have seen them have 1,2, or 3 cylinders not working on the same side. The stator or switch boxes can cause this but you have eliminated the switch boxes as you stated you replaced them. Do you have a timing light? If so I can walk you though a test on using it to verify if it is running on 3,4,5 or 6 cylinders.

It could still be an injector driver in the ECU as it fires the injectors in pairs so it could be running on 4 cylinders. If you have the motorolla ECU (2002-up) it fires them individually. A motorolla can cause the loss of 1 cylinder.