Hesitation at wot help

[dogmam]

Hi i just got this 2002 mercury xr6 150 the motor has very little hrs on it so the first time i took it out when you go to get on plane it hesitates for a few sec and then takes off and runs fine so i took it to someone that works on boats he said it was my oiler and said it would clear up after a few tanks of gas it didn't so i replaced the fuel pump rebuilt the carbs it did not fix the problem so i checked the reed valves non were damaged but some of them were not seated on the rubber face should there all be seated or not? I replaced them with the new carbine fiber ones and some of them don't seat on the rubber face could this be my problem with the hesitation at wot

 

[Chris1956]

Your mechanic's suggestion your oiler was responsible for hesitation, is way off base, IMO. He seems to suggest that so much oil was mixed into the gas it would foul the plugs upon acceleration, but not at high speed or idle. That would be unusual.

Check your fuel pump for diaghram leakage. When they leak a bit, raw fuel gets into the crankcase and partially floods the motor at low speed. They can still run OK at idle for a while. When you accelerate, the motor hesitates due to an over rich condition. It takes several seconds of high speed running to burn up the fuel.

Reed valve sealing issues would only affect idle quality. If the motor idles well, the reeds are working fine. Also, the OEM reeds almost never wear out.

Carbs could be an issue as well. Is the enrichener is working properly? If that stuck open it could help flood the motor at idle.

 

[dogmam]

Your mechanic's suggestion your oiler was responsible for hesitation, is way off base, IMO. He seems to suggest that so much oil was mixed into the gas it would foul the plugs upon acceleration, but not at high speed or idle. That would be unusual.

Check your fuel pump for diaghram leakage. When they leak a bit, raw fuel gets into the crankcase and partially floods the motor at low speed. They can still run OK at idle for a while. When you accelerate, the motor hesitates due to an over rich condition. It takes several seconds of high speed running to burn up the fuel.

Reed valve sealing issues would only affect idle quality. If the motor idles well, the reeds are working fine. Also, the OEM reeds almost never wear out.

Carbs could be an issue as well. Is the enrichener is working properly? If that stuck open it could help flood the motor at idle.

Chris thanks i have rebuilt the fuel pump the dirhams were bad so i put in a new kit i will look at them one more time do you think i could have a bad kit,? i also rebuilt carbs, is the enricher where the oil mixes with the gas im not sure where it is sorry also could my fuel tank vent have anything and thanks for the help i have tried everything and nothing seems to help i have put in a new primer bulb still no change new gas lines on the motor

 

[Chris1956]

The enrichener is the choke. On my '93 Merc V6 a solenoid opens with the choke button, and drains fuel from the top carb bowl, into the throats of the other two carbs to enrichen the mixture.

You could unbolt the fuel pump from the block and pump the primer to see if it leaks past the diaphragm.

The oil pump pumps oil into the fuel line via a tee, above the fuel pump. Oil is gravity feed to the pump, from the motor mounted reservoir.

I would not think the fuel lines or primer bulb would cause your issue.

If that doesn't fix it, maybe one of your carbs has a bad inlet needle, float or the float height is too high, allowing slight flooding of the carb.

 

[dogmam]

The enrichener is the choke. On my '93 Merc V6 a solenoid opens with the choke button, and drains fuel from the top carb bowl, into the throats of the other two carbs to enrichen the mixture.

You could unbolt the fuel pump from the block and pump the primer to see if it leaks past the diaphragm.

The oil pump pumps oil into the fuel line via a tee, above the fuel pump. Oil is gravity feed to the pump, from the motor mounted reservoir.

I would not think the fuel lines or primer bulb would cause your issue.

If that doesn't fix it, maybe one of your carbs has a bad inlet needle, float or the float height is too high, allowing slight flooding of the carb.

thanks for your help i will try it this afternoon when i get of work