Mercury carburettor.

[jamie N]

Trying very hard and patiently, to locate a replacement carb for my 2006 Mercury 4HP. Found a new one on Ebay at about £35, and ordered it giving the model number of the engine, and asking if it was the right carb. The retailer told me that although it looked the same, it was incompatible. OK, that's life.
I did then find one with the right part number, which is £200 more expensive, from a different supplier.
WTF?
The carb which came with the engine appears to be a non-standard one from Keihin, with a number of 3CG8AG7, which I've been unable to find any reference for anywhere, which is curious?
As a genuine question, how is it that there seem to be so many different models of carbs, which seem identical, for this engine?
Whilst I continue searching for a 803819A05 compatible carb, or for spares to fit the same, if anyone knows of a Mercury dealer or a Tohatsu agent that can supply this for me, it's worth a virtual bottle of 'The Hearach'.

 

[Beneteau381]

Trying very hard and patiently, to locate a replacement carb for my 2006 Mercury 4HP. Found a new one on Ebay at about £35, and ordered it giving the model number of the engine, and asking if it was the right carb. The retailer told me that although it looked the same, it was incompatible. OK, that's life.
I did then find one with the right part number, which is £200 more expensive, from a different supplier.
WTF?
The carb which came with the engine appears to be a non-standard one from Keihin, with a number of 3CG8AG7, which I've been unable to find any reference for anywhere, which is curious?
As a genuine question, how is it that there seem to be so many different models of carbs, which seem identical, for this engine?
Whilst I continue searching for a 803819A05 compatible carb, or for spares to fit the same, if anyone knows of a Mercury dealer or a Tohatsu agent that can supply this for me, it's worth a virtual bottle of 'The Hearach'.

Why do you need a new carb? All carbs are cleanable if that’s the issue

 

[Steve_N]

I suspect that the Keihin number is a serial number rather than a model no. On mine (Mariner 4hp Sailmate of the same vintage) it was 3CGBVH1 which equally doesn't yield any search results.
I replaced it recently with Ebay item 153586473090 and the motor runs perfectly. For £30 I didn't worry about any detailed compatibility checks.
The Keihin carb was beyond cleaning as it's inner surfaces were corroded (perhaps from the ethanol in E10) releasing particles that obstructed the jets. The float bowl in particular was a right mess.

 

[Beneteau381]

I suspect that the Keihin number is a serial number rather than a model no. On mine (Mariner 4hp Sailmate of the same vintage) it was 3CGBVH1 which equally doesn't yield any search results.
I replaced it recently with Ebay item 153586473090 and the motor runs perfectly. For £30 I didn't worry about any detailed compatibility checks.
The Keihin carb was beyond cleaning as it's inner surfaces were corroded (perhaps from the ethanol in E10) releasing particles that obstructed the jets. The float bowl in particular was a right mess.

The ethanol doesn’t corrode, it absorbs water, we leave it in the bowl, running dry doesn’t work, a small amount is left, the ethanol;petrol evaporates leaving a globule of water which then corrodes the fuel bowl and the bits block jets.
I advise to always drain the bowl, don’t switch off the fuel tap, it doesnt empty the bowl completely
Ive found as you have that cheap Chinese carbs actually work ok and you can actually adjust the pilot jet mixture

 

[jamie N]

Why do you need a new carb? All carbs are cleanable if that’s the issue

Good point and one that I'd thought as well having cleaned quite a number of carb's over the years, but the brass jet is totally corroded into place, and won't turn. I tried soaking in WD and using increasing amounts of force, to the point that I was using an 'easy out' drill which failed also.
@Steve N, thanks for the info, and based on your experience I went onto that Ebay site and:
Happily though, because of their bigotted stupidity in denying the largest area of the UK access to their product, I went to a rival in Wales, and found an equivalent which should arrive in a week.
As a slight aside the present carb is:
I wonder whether the main model/type is the 3CG, and the rest just a more refined ID/version?