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

 

[Dukedog]

chris has ya goin' in tha right dirrection.. its gonna be fuel delivery... oiler has nothin' ta do with it.... being a '02 its gonna be whats called an electronic motor (non switch box).. its possible tha ecm may have a glitch... jus gotta keep lookin' for it... gl.

 

[dogmam]

chris has ya goin' in tha right dirrection.. its gonna be fuel delivery... oiler has nothin' ta do with it.... being a '02 its gonna be whats called an electronic motor (non switch box).. its possible tha ecm may have a glitch... jus gotta keep lookin' for it... gl.

Thanks I have run myself crazy and still not got it running right I have checked the enricher when I took off one of the gas lines and keep pushing the primer bulb no fuel came out of with motor not running where is that ecm located at

 

[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.

So when i take off the gas line that comes off of the top of the middle carb#2 when i prime the the primer bulb should gas come out of it that goes into the enricher so with the top carb gas line that goes to the enricher nothing comes out of that line when I pump the primer bulb do you think the 2 line could be crossed

 

[dogmam]

So when i take off the gas line that comes off of the top of the middle carb#2 when i prime the the primer bulb should gas come out of it that goes into the enricher so with the top carb gas line that goes to the enricher nothing comes out of that line when I pump the primer bulb do you think the 2 line could be crossed

Xhris never mind what i said the line i thought was coming from #2 is really #1 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.

Chris so I checked fuel pump no leaks the enricher seems to be fine I have checked the carbs took them apart floats are fine a level blew out all the ports and jets what else could be the problem

 

[Chris1956]

All I can think of at this moment is water infiltration. Water can get into the cylinders and foul some spark plugs, causing them to misfire until high speed can overcome the water. If some of your spark plugs are real clean compared to others, that is a good bet.

 

[dogmam]

All I can think of at this moment is water infiltration. Water can get into the cylinders and foul some spark plugs, causing them to misfire until high speed can overcome the water. If some of your spark plugs are real clean compared to others, that is a good bet.

They are all the same what about the ecm if it's not working properly can it be the problem and thanks for all the help

 

[dogmam]

All I can think of at this moment is water infiltration. Water can get into the cylinders and foul some spark plugs, causing them to misfire until high speed can overcome the water. If some of your spark plugs are real clean compared to others, that is a good bet.

The sparkplugs all have gas on them

 

[Chris1956]

Does that motor have an ECM? I see CDM ignition, but no ECM on the parts list.

Do you have an idle stabilizer? If so, you might disconnect it, as they can alter the ign timing in bad ways.

 

[jimmbo]

So this is a New to You Motor?
A bog/hesitation when the Throttle is advanced can be due to many Issues, often a lean Fuel Condition. Did the Previous Owner give you any Maintenance/Repair History?
How long did the Motor sit since it last ran?
Was the Fuel System drained, or a Fuel Stabilizer used?
A check of the Carb to Ignition Advance, known as a Link&Sync, may be in order, as previous Owner may have taken the Carbs off
Do you have any Compression Numbers?

 

[dogmam]

So this is a New to You Motor?
A bog/hesitation when the Throttle is advanced can be due to many Issues, often a lean Fuel Condition. Did the Previous Owner give you any Maintenance/Repair History?
How long did the Motor sit since it last ran?
Was the Fuel System drained, or a Fuel Stabilizer used?
A check of the Carb to Ignition Advance, known as a Link&Sync, may be in order, as previous Owner may have taken the Carbs off
Do you have any Compression Numbers?

Jimmbo no I have no maintenance records he just told me it was only ran a few times a yr he said it ran fine hers whats been done all cyclinder are reading 100 psi I have rebuilt the carbs rebuilt fuel pump flush out tanks and ran 3 tanks of gas i did the link and sync when I looked at the reed valves there are 4 to 6 reeds when you hold it up to the light you can see daylight the gap is somewhere around .010 to .015 all new plugs once you get it up and going it runs fine it spits and backfires randomly at idel I have read where the reed valves need to be seated on the rubber is this true

 

[dogmam]

Does that motor have an ECM? I see CDM ignition, but no ECM on the parts list.

Do you have an idle stabilizer? If so, you might disconnect it, as they can alter the ign timing in bad ways.

Its a 2002 motor i did read that if the reeds are not seated on the rubber it will idle and my problem of hesitation at wot but I am seeing so many different things on this i am not sure what way to go i think im got to pull reeds sand down the rubber and get the reeds seated and reinstall and see what happens it that don't work then it' timing or electrical i think thanks for all your help

 

[Chris1956]

After you rebuilt the carbs, did you set the idle mixture on all six carb throats for a smooth idle? If so, the idle mixtures maybe set too lean to accelerate.

Most Mercury carbs do not have accelerator pumps. Therefore the carb idle mixtures need to be a bit richer to compensate. You might try richening the mixture screws 1/8 of a turn and then test acceleration. Richen the #1 cylinder carb throat first and then test acceleration. Repeat with #2 carb throat and so forth, testing after each adjustment.

 

[jimmbo]

100 psi on that engine sounds Low. I would redo the Compression Test with a different Gauge. Don't start sanding the Reeds, as that will result in you needing to find Replacements. They are Check Valves, and if there is a slight gap at rest will, 99.999+% of the time, will seal when crankcase pressure rises.
Can the Spark, jump a 3/8" Gap, on all Cylinders?
When you rebuilt the Carbs, did you use genuine Mercury/Quicksilver Parts?
How did you check/adjust the Float Levels?
A Serial Number would be nice, as there are 4 Groups of Serial #s for the XR6 and there are variations of the Carbs between them, and even within them.
It appears some have non adjustable Idle Mixture Circuits.
When you did the Link & Sync, where did you get the Specs for it?

 

[dogmam]

After you rebuilt the carbs, did you set the idle mixture on all six carb throats for a smooth idle? If so, the idle mixtures maybe set too lean to accelerate.

Most Mercury carbs do not have accelerator pumps. Therefore the carb idle mixtures need to be a bit richer to compensate. You might try richening the mixture screws 1/8 of a turn and then test acceleration. Richen the #1 cylinder carb throat first and then test acceleration. Repeat with #2 carb throat and so forth, testing after each adjustment.

I have done that if have went out as far as 3 turns still hesitation at wot