HELP Mercury 5.7 willnot idle

[alldodge]

no its a carb 864943

If your serial number is 0W864943 then you should have fuel pump Merc part number 861154A3. See link below for parts breakdown
http://www.mercruiserparts.com/Show...12834&bnbr=60&bdesc=Fuel+Filter+and+Fuel+Pump

 

[JBlow]

861155-4 is the number on it

 

[achris]

If your serial number is 0W864943 then you should have fuel pump Merc part number 861154A3. See link below for parts breakdown
http://www.mercruiserparts.com/Show_...+and+Fuel+Pump

I think he's saying the number on the carb is .... It's not the engine serial (checked it and it comes back as a 2.00:1 drive)...

JBlow, what is the engine serial number? We still don't know if this is a TKS carb or a fuel injection engine. If it is a TKS, you may have a problem with the TKS wiring, or the coil inside the carb.... or even a leaky plunger.

Chris......

 

[JBlow]

I don't know the engine number and the boat isn't at my house I know the other numbers. carb # 864943 fuel pump # 861155-4 I can get the engine # tonight.

 

[JBlow]

here is the carb http://www.*****************/parts/me...urator-mercarb

 

[JBlow]

[No message]

 

[achris]

OK, that's a Mercarb. The fuel pressure should only be 4-7psi. I would also put a section of clear in the fuel line between pump and carb to make sure you're not getting any air sucked in (leaky fittings etc)....

 

[midcarolina]

There's a lot of info flowing here, and I am not trying to muddy the water.......... but I think there may be some terminology issue here, If your buddy is a auto mechanic what he is likely calling a high pressure carb fuel pump is 4.5 - 9 psi a low pressure is 1 - 4 psi ( in vehicle terms )

I say this cause I can see no way the needle and seat could hold 40 psi at all........ at that pressure it should be dumping a lot of fuel down the carb throat.....

I would still verify pressure with a gauge........ and would do as Chris suggests with a clear tube, cause I still think you have a lean idle condition.

 

[JBlow]

buddy is a boat mechanic but judging from him looking at certain things he not a good diagnosis nor will he be my boat mechanic. he told me " its a high pressure pump there is a low and a high there like $200". anyways i ordered a new pump be in shortly il make up a clear hose and il test the pump at work. hopefully the new pump fixes it. i did notice OEM pumps are black and this one is not so tells me its been replaced before.

 

[JBlow]

i can say theres some pressure on it. i put my thump on it and its sprayed like a garden hose a garden hose is (60psi city pressure) no way 4 to 9 psi would do that.

 

[alldodge]

buddy is a boat mechanic but judging from him looking at certain things he not a good diagnosis nor will he be my boat mechanic. he told me " its a high pressure pump there is a low and a high there like $200". anyways i ordered a new pump be in shortly il make up a clear hose and il test the pump at work. hopefully the new pump fixes it. i did notice OEM pumps are black and this one is not so tells me its been replaced before.

I think after installing a low pressure pump you will be in good shape. Let us know how it works out

 

[JBlow]

ok so put new fuel pump in Friday night and nothings changed. we did figure out the float at the stem a bent. I tried blowing in it and got no air threw it. I re adjusted everything to the proper measurements and to where I could blow in the inlet of the carb and push the float up shut it off BUT no change still will not idle. we did play with the choke by hand to get it to idle up and run to put it in gear so we did that all labor day every time we stopped. it ran great other than that. I think iv had enough i am going to take it to somebody.

 

[JBlow]

Talked to a boat mechanic yesterday and he said he had the exact same problem with a carb about a year ago and could not figure it out said he spent hours and days pulling his hair out said he bench tested it and couldn't get it to fail as soon as he put it on the boat it wouldn't idle. he ended up ordering a reman carb from summit and it did the same thing then he bought a brand new carb and it worked perfectly fine.only thing he could think of was Japanese kits and carbs maybe the holes are drilled a little bigger or something like that. He has a carb he going let me try out and if it works he going sell it to me.

 

[alldodge]

Talked to a boat mechanic yesterday and he said he had the exact same problem with a carb about a year ago and could not figure it out said he spent hours and days pulling his hair out said he bench tested it and couldn't get it to fail as soon as he put it on the boat it wouldn't idle. he ended up ordering a reman carb from summit and it did the same thing then he bought a brand new carb and it worked perfectly fine.only thing he could think of was Japanese kits and carbs maybe the holes are drilled a little bigger or something like that. He has a carb he going let me try out and if it works he going sell it to me.

Appreciate the update and hope it works out.