Mercury inline 6 150hp rough idle

sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

I found a pin hole in the one of the fuel lines near the tank. Something so small could cause so much hassle. That's why I had to have the mariner 15hp's bulb rock hard or it would die and stall. The I6 must struggle in a big way when it suck air bubbles.
I wanted to take the family out in the boat soon, might be able too :)
 
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Maxz695

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Re: Mercury inline 6 150hp rough idle

Alright Hope that did it Have a wonderful safe trip and write back with the details. I had the same issue at the tank hose connection. all looked good so iI never messed with it. One day I redid it and wala. Problem solved. I hope this thread is closed after that. Best wishes Scincerly Max695
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

Thanks max, I appreciate your valued advice. I tryed mucking around with the fuel lines, I couldn't stop the bubbles. The needle and seats can't handle the electronic pumps fuel pressure. So I stopped using that pump.
Seems to get very little bubbles on motors fuel pumps. The flow is a slow dribble on fast idle. I guess I will water test again.
If I can't get on top of it soon I will get it looked at by mercury mechanic, there's a month wait to get it looked at. I don't mind working on it, just struggling for time. I might just get them to do the link& sync.. :)
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

Just an update on my progress. I haven't tested it out since I put kits through the fuel pumps. I tryed to find someone who will do the link& sync but I was unable to find anyone! They refuse to work on the motor cause they think its to old! Crap! They either refuse to return my calls or just say its to old.
I want to do a compression test again.

Is it possible that incorrect float level could effect it getting on to a plane? I beleave so. It's one area I haven't really looked into.
IMAG0107.jpg

This one looks set different compared to the other two, maybe cause one float is different to the rest. That's not right. I can gather the fuel bowl won't fill up as much. I will check all the gap settings according to clymer manual. I think its got to be flat from "post to post" this isn't!
IMAG0108.jpg

One float is different to the rest, I will put it all back together and water test again.
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

Just bought a mercury workshop manual on eBay, I have always followed the clymer manual, not anymore.
Can't wait to start reading it, happy days!! ;)
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

Just done compression check:
#1- 140
#2- 150
#3- 145
#4- 150
#5- 145
#6- 140
Motor was cold too :)
 
M

Maxz695

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Re: Mercury inline 6 150hp rough idle

The way the levers are set will not allow the fuel bowls to fill fully and gas will not be readily available to pull through the main jet at higher RPMS. There will not be enough fuel to support it. The spring may not be right the float level even though considered unajustable must still be checked. The bar as you stated top picture top lever should be level end to end it looks as though the wrong needle is inserted in the seat. Here is another poster with this type of problem. Read Gerry,s advise here http://forums.iboats.com/mercury-mariner-outboards/my-bowl-runneth-over-589701.html From what I can see or tell the last float,s spring (Dark one) has a more proper distance for that carb set up. The first looks to far in the second has a kink. I would go with reseting the levers using a proper needle for that carb and using the third float. I could be wrong if the levers are not fully closed in the picture. Tip it upside down levers facing up and the bar should be even and level.
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

Interesting read there max.. mmm. The darker float is about a 1mm shorter in height than the other two. I might getting two critical here. It never had any problems once it got onto a plane, just beforehand.
The spark plugs are oil fouled again. So it sounds like carb issues. Getting way to much fuel probibly. I use 98 octane fuel with valvaline synthetic oil. I haven't tested the motor since I got new kit through the fuel pumps,maybe a hole in the diafram.
 
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Maxz695

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Re: Mercury inline 6 150hp rough idle

Too much gas can be from the "not level levers" making the needle stick or not seat properly. Pressure is lost by way of not enough leverage being semi level to close the needle tightly. I would get a proper float for the engine. I see now it is not the correct one. someone messed with the needle and the float in it. A full kit is recommended. Heres and edited pic of the levers View attachment 179691 If you look at this picture you,ll see the needle is closing but the float will not be as high as it should and therefore the bowl is not full when closing the needle. You ma be able to bend the lever touching the needle to make the one that contacts the float spring and bring it to the proper setting View attachment 179692
 
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Maxz695

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Re: Mercury inline 6 150hp rough idle

No it is very critical to have the proper needle seat close and float level at the proper hight in unisen. That may be why the spring is 1 mm taller than the other floats and should compensate the difference.The darker float appears to me just like the one off my 79 40 HP. It is deffinitley a replacement someone put in there. It may sitll work but you have to adjust the lever at the needle to get the float lever level. Man thats hard to explain but a simple task. If it,s not level the float bowl won,t be full for the high speed jet to work properly
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

You have made a good point there! Something so small could make a mess of how the motor runs. I paid $2500 for this motor 7 years ago. The old fella who re conditioned it was a retired engineer. Apparantly if you touched anything on the motor he would get uneasy, like you might harm the motor is some way.
I don't think the motor was not tested properly after rebuild cause it had a V6 gearbox which made it difficult to plane,it was out of tune. He must have thrown in that float thinking it was ok maybe.

Ill ring around and chase up floats etc..
Thanks :)!
 
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CharlieB

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Messages
5,617
Re: Mercury inline 6 150hp rough idle

Maxz695 said:
.............There is a little rubber gromet in the seat or a rubber tip on the needle that may be bad as well and may still leak after adjustment is made. JMO
Click to expand...

Depending on what supplier provided the parts for a carb kit,

EITHER a rubber tipped needle

OR a solid needle with a rubber O-ring that must be pushed into the the carb to become the seat

The overall length of either should be very close to the same so adjustment/bending of the levers is small amount.
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

Top stuff! Just ordered 3 new floats $40. Thanks max.. good man! I have a full gasket kit I will see what's in it.. don't recognize some of the small bits it.
 
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Maxz695

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Re: Mercury inline 6 150hp rough idle

Good to hear I hope you get at least 1 needle and seat to replace that wrong one with. Let us know how you make out.
 
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Maxz695

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Re: Mercury inline 6 150hp rough idle

CharlieB This is in reference to this picture View attachment 179715 This needle and seat are in the sealed position with the levers as seen in an unlevel position when hence wrong needle and or seat. Possible as you state rubber tip needle and a seat with the oring gromet. Unmatched pair
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

The needle is all plastic. There's no wear on the point of the needle,but I didn't look inside the seat for a rubber seal. Will investigate later.

The bottom fuel pump was missing the gasket too.you know how's there's two and the diafram is between them.

Update: needle seat looks good, but looks don't always mean much. Before When I tryed to connect the electronic fuel pump one of the carbs started leaking out of its throat. I'm guessing it was the one with the dodgey float/linkage.
So when the motor was idling theres not much pressure but once Its above idle the pressure goes up causing the needle&seat to leak fuel. Will test again when I get new floats and adjust linkages again..
I read somewhere that boat motors don't produce much fuel pressure, so thats why I thought the electronic fuel pump caused the carb to leak, to much pressure from it.
 
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Maxz695

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Re: Mercury inline 6 150hp rough idle

They sell more than one pressure fuel pump. 6lbs usually used on car carburetors and high pressuer Not sure of the out put pressure, but it,s for fuel injection I had used a hight pressure fuel pump on my car with a carb and had major leaking. I don,t know if i,m correct or being clear but I,ll try one more time. If the needle is fully closed in the picture you posted View attachment 179735 and the top lever showing a slight angle It is the wrong needle for the seat and must be replaced . A rubber tip needle can only be used with a solid brass seat. A solid needle can only be used with the seat with a rubber gromet Oring. They also have a little copper washer before inserting the seat. You cannont use a needle with a rubber tip and a seat with a rubber gromet Oring. It will not properly seal hence to much gas as well as float level being off, Let me ask you this are the other needles plastic like the one in the picture? Does the seat look the same as the others. We already know someone changed the float with the wrong one. You need to have the proper needle and seat. and refer to my picture of the levers for comparison to proper lever position. I guess it could be the needle in the picture is not fully seated and i,m going on about nothing. View attachment 179736
 
sourbsted

sourbsted

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Re: Mercury inline 6 150hp rough idle

http://i304.photobucket.com/albums/nn186/greenmk2/IMAG0109.jpg[/IMG
[IMG]http://i304.photobucket.com/albums/nn186/greenmk2/IMAG0110.jpg
All the needles are plastic.. they all have rubber seats inside brass fittings. I'll ring around today and see if there are any replacement needle& seats available. There expensive around here. $30 each. That copper washer looks pretty worn ay :)
IMAG0109.jpg
 
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