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Mercarb 2 BBL Carburetor

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stumped123

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Can someone give me some point

Can someone give me some pointers on how to adjust the float? The specs I have do not tell where on the float to measure from.

This is from a 89 3.0L on a 89 Larson Bowrider.
Carb No. 1389-9562.

Sure would appreciate any help.

Thank you most kindly.
 
Use the line on the side corne

Use the line on the side corner on the end of the float where the metal stem attaches to the float for the horizontal reference plane. Make the measurements for adjusting the float w/the gasket held in place so its thickness is included in the measurement.
 
"Be careful with the specs in

"Be careful with the specs in aftermarket rebuild kits. Use these.<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_pdf.gif""" align=left alt=""application/pdf"">
[url=""][b]97_08.pdf[/b][/url] (50.4 k)</td></tr></table></center>"
 
"Thank you, Guy, Steve jay and

"Thank you, Guy, Steve jay and Troy, for the info and reference links.
I also found some Mercury procedures, which were most helpful.
One mystery - I found two different ways of putting the fuel inlet spring into place. One shows it going inside the screen filter, the other shows it going against the flat side of the filter and directly into the carb structure.

I think the latter is correct, in that it keeps the filter tight against the opening.

???

Thanks again, guys."
 
"Another question regarding th

"Another question regarding the carb.
I noticed that the choke thermostat is always "hot" electrically anytime the ignition key is on, even after the engine is warm.
Can anyone explain why?
Thanks."
 
Merc. was too cheap to put a t

Merc. was too cheap to put a thermostatic switch on it to control on/off automatically. You can install a relay before the choke w/a dash switch control.
 
"Thanks, guy. I kept wonderin

"Thanks, guy. I kept wondering why the battery discharged if the engine was off, but the key was accidentally left on.

Now I know."
 
The question about the spring

The question about the spring and the filter in the Fuel Inlet is still open.
Anyone know which is correct?

Thanks.
 
"Thanks for the quick response

"Thanks for the quick response.
Maybe the Merc manual for this engine and carb is wrong. If you have access to the manual, The section on Fuel System, page 5C-10, has an exploded view of the carb, similar to the one in your link, which is also similar to the one from my Clymer Manual. However, in the Merc manual the spring is shown on the opposite side of the spring. Also, on page 5C-5, the procedure and illustration are clear that the spring goes in the carburetor body, and the filter goes open end to the filter nut.
Why could the manuals be opposite of one another? Was there a tech bulletin published by Merc after their manuals were printed?
I"m not trying to start a p'ing contest, I would just like to be sure. My reasoning is that if the spring goes against the bottom of the filter, it would ensure that the open end is always against the input opening. If it goes inside the spring, it might push the filter away from the opening, and allow contaminants into the carb.
Am I all wet? I know experience is worth a ton of book learning, so I would just like to understand why Merc is not the same.

Again, thanks very much for your response, and I do appreciate you taking the time to answer.

This boat is old, but it's fairly new to me, and it's like my baby, if you know what I mean.

Thanks again."
 
"is there a cork gasket attatc

"is there a cork gasket attatched to the filter itself and if so, which end is it attatched to??"
 
No cork gasket. The old filte

No cork gasket. The old filter and spring was the same as in the Quicksilver Fuel Filter Kit (1397-8767Q).
 
"From my automotive experience

"From my automotive experience, I believe that the purpose of the spring is to hold the filter against some sort of seal or gasket. Without a gasket, dirty fuel could easily by-pass the filter. I am seeing a round seal inside the fuel inlet connector and it would seem the filter spring should be pushing the filter against this gasket to prevent any dirty fuel getting past The diagram is not the best but looking directly at the parts, you should be able to determine what goes where. If what i said is correct, it would seem that the spring should be on the other side of the filter. I am assuming the open side of the filter goes toward the fuel connector nut and that the dirt is trapped on the inside of the filter."
 
"Thanks, but could you clarify

"Thanks, but could you clarify that response just a little? I'm not sure which one is "this one" and which is "the other one".
Sorry, maybe I'm just a little slow.
Thanks, again."
 
"Bobbyc- your response is in l

"Bobbyc- your response is in line with what I am thinking, which means the Merc manual is correct.
In other words, it's supposed to go together like this: 1. Put the spring into the carb body. 2. Put the gasket in the filter nut. 3. Put the washer on the nut. 4. Put the filter into the nut so that the open end is toward the end where the fuel line goes onto the nut, and the closed end is against the spring.
Does this sound right to you?
Thanks for your response."
 
""My reasoning is that if

""My reasoning is that if the spring goes against the bottom of the filter, it would ensure that the open end is always against the input opening. If it goes inside the spring, it might push the filter away from the opening, and allow contaminants into the carb."

You make an excellent point. Perhaps the reason I had granular varnish in the bottom of the carb bowl was due to installing the screen filter first. Too bad that both of the diagrams do not provide the spring's length. I would think if the spring is too long that it would crush the screen filter or push the screen's solid base toward the fuel line and block the carb bowl inlet."
 
"That is correct...in automoti

"That is correct...in automotive applications, some filters actually have the cork washer attatched to the open side of the filter. The spring should always push the filter against the washer to make an effective seal...The merc manual is correct!"
 
"Well, guys, this has been ver

"Well, guys, this has been very enlightening for me, and hopefully for others as well.

Thanks so much for the responses. I only wish I had found this website BEFORE I replaced the water pump, the bellows, the xx*#zz water hose, the fuel pump, all of the gas that had been sitting in the tank for 2-3 years, tearing down the carb and putting it back together I don't know how many times, taking up the floor over the fuel tank, figuring out how to get ALL of the old gasoline/ethanol crap out of the tank, etc. etc.
(Boat was unused for several years for numerous reasons of health, etc., which is what started my problems back in June.) I hope I'm now near the end of the boat problems.
Anywho - a great big thank you to all. You have a wonderful forum here, and I really appreciate all you have contributed."
 
"Sounds Like me.... I just got

"Sounds Like me.... I just got a 91 searay with a 3.0 mercrusier. Was sitting for 2 years , not winterized etc.... Replaced starter and cleaned both carb and fuel pump filters . Now she finally starts but you have to pump the throttle and then under load she stalls.... Thinking carb needs a rebuild. Ran engine out of a 5 gal gas can becase I know the gas in the tank is bad. Also , got most of the gas out of the tank but still more in there so how do i get the rest out??? Anymore suggestions would be gladly appreciated. Thanks in advance, Mike
PS is it hard to rebuild this carb or should i have it rebuilt? Also does anyone know where to have it rebuilt? Thanks again!"
 
"Mike:

It's a 2 BBL and

"Mike:

It's a 2 BBL and couldn't be easier. Just use the carb settings from a manual and make sure you go to a dealer and get the correct THICK base gasket. Get a new float, and accel. pump if not included in the kit. Use compressed air to blow the crud out of the idle circuits and soak the bowl and rods again to ensure it gets all the hardened varnish out."
 
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