Carburetor's

[Smaj]

Hello, I have a 2002 Mercury 90hp Elpto I am getting ready to attempt to clean and repair the carburetors. I would like to know if someone could tell me if the 3 Carburetor's are the same and if it matters in which order the get installed. They all look the same to me and I cannot find anything that tells me different. Also, to let you know the reason that I am doing this is in testing the number 3 cylinder seems to be having a problem getting fuel and would only fire periodically. There also seems to be a problem with fuel consumption, even sitting at idle in the driveway it will suck the gas and seems to have excess from the exhaust like maybe the float is stuck. Any Help would be appreciated.

 

[ThomW]

Hello, I have a 2002 Mercury 90hp Elpto I am getting ready to attempt to clean and repair the carburetors. I would like to know if someone could tell me if the 3 Carburetor's are the same and if it matters in which order the get installed. They all look the same to me and I cannot find anything that tells me different. Also, to let you know the reason that I am doing this is in testing the number 3 cylinder seems to be having a problem getting fuel and would only fire periodically. There also seems to be a problem with fuel consumption, even sitting at idle in the driveway it will suck the gas and seems to have excess from the exhaust like maybe the float is stuck. Any Help would be appreciated.

Is this a 2-stroke or 4-stroke motor? You will want to keep the carbs in the same order they are on the motor, as the way the fuel lines attach is set up for them to be top, middle, and bottom. Depending on what motor you have, there will also be a syncing process you will need to do when reinstalling the carbs.

 

[Smaj]

Thank you for the information. I can do that and makes sense. The next question I have is in ordering the repair kit 8112231 is shows 2 gaskets of the same kind. The carb only has one. Am I missing something? the one's in the middle I am talking about and it goes in the upper cover plate where the idle mixture screw is. Any Idea as to why two of them?

 

[racerone]

Check the fuel pump diaphragm first.

 

[OCboat]

A lot of the repair kits cover multiple motors so sometimes there are gaskets and washers that aren't used for a particular motor. My the kit for my motor always includes a few things that I don't use.

 

[Smaj]

I will check the fuel pump diaphragm, but doesn't make sense is the other two carbs and cylinders are firing great that the third wouldn't be getting fuel also but 2 out of 3 getting gas when the line coming from the pump is a daisy chain. could be wrong but I will check. Thank you and as to the gasket set, didn't think of that. Thank you as of right now waiting on parts. lol I will let you know.

 

[racerone]

If there is a hole in fuel pump diaphragm then 1 cylinder might be flooded and cannot ignite that fuel.-----And that fuel will go right through the motor and out the exhaust.

 

[Smaj]

racerone, are you saying that there is a fuel pump diaphragm on the carb? I don't see anything that list or shows anything like that. but if we are talking about the actual fuel pump 14360A71 and if so again if the fuel is pumped into the carb from a daisy chain fuel line to the carbs how could one and two get fuel and not three? Sorry I am just confused.

 

[racerone]

Oh well----I am wrong again I guess.----But are you aware that your motor has 3 separate crankcases ?

 

[Smaj]

Yes Sir I am aware of that. That was the main reason for asking about the carbs if they were the exact same. I was going to switch it up say 1 to 3 and 3 to 1 and see it the problem was the same. but was suggested not to switch them up. go with top middle and bottom.

 

[boscoe99]

What is the engine serial number?

If you check the Mercury parts catalog I suspect that you will see that the carburetors have different part numbers. To indicate which carburetor goes into which position.

 

[boscoe99]

For instance

 

[Dave1027]

The difference is likely just the nipples the fuel lines connect to.

 

[Smaj]

I want to thank all for the information I was aware of the 3 part numbers, and was made aware of top middle bottom by Thom W due to the fuel line connection set up. The Nipple as to Dave1027. Thank you

 

[racerone]

The 3 carburetors all operate the same and feed one cylinder.-----It is linkages / fuel connection that give them different part numbers.

 

[Smaj]

Morning everyone, Well the Carbs are rebuilt and installed. But I also like to check the timing prior to trying to start. I understand how to do it, but I am confused about the timing specs. The manual states that the Idle timing is 2*ATDC - 6* BTDC and the WOT timing shows 20*BTDC. The WOT timing doesn't seem to be a problem. but in the idle timing ((is it stating that the timing should be set between 2*ATDC - 6* BTDC ))""so the timing could be 2* BTDC""???? A little confused about the gap. can someone clear it up for me. Thanks

 

[Chris1956]

I hope you are reading the timing specs a bit wrong. Idle pickup timing is the point when the carbs are still closed, but ready to open. You need to set the throttle to the point when the carbs are just ready to be opened by the linkage. That is when you want the 2*-6* ATDC.

Double check that spec, as none or not many of the ADI motors want an idle pickup spec of BTDC. Idle pickup timing is set and not changed, when setting idle speed.

Idle pickup timing is different from idle timing. Idle timing is achieved by retarding the throttle until the idle RPM is correct.

 

[Smaj]

Well I could be reading it wrong but don't think so. Looking at the manual right now under tune-up specs, Idle timing (NOT idle pickup timing) 90 HP states 2* ATDC - 6* BTDC. So I guess my question is am I supposed to set the timing anywhere in between the 2* ATDC - 6* BTDC ?

 

[Chris1956]

Is that a Mercury service manual? The Clymer and Seloc service manuals often have big mistake in their instructions. I am not an expert on your motor, but all of the other motors that I have seen with ADI ignition have a spec for idle pickup timing that is in the ATDC range. I have never seen a Merc that specified idle timing, nor one that had a range from ATDC to BTDC.

 

[Smaj]

Chris1956, No it's not a mercury manual, it is the Seloc. I will try to find the timing settings from another source and see what I can come up with. I want to say that the timing is probably at the 2*ATDC but will make sure before trying anything. I think you for your help. I will keep you up to date.