Stripping a carb

[lustyd]

Hi all, I'm planning to strip my carb this weekend in a bid to stop a performance issue with the outboard. Being less mechanically minded I could use a few pointers. I have the carb cleaner and tools, just need to know which bits to remove and clean. The picture and link below are my carb model. From previous experience the float valve (6) is rubber tipped and I was warned not to soak this in cleaner.

Should I be removing all of the parts shown in the diagram for cleaning? Will I then need to adjust anything when I put it all back and if so, how?

http://www.boats.net/parts/search/Merc2/Mariner/4-5/9589154%20THRU%200P016999/CARBURETOR/parts.html

Thanks very much
Dave

 

[30boat]

Bits to clean are the jets(3)(4) and float valve (6)seat.Also clean the adjuster screw (30)passage but take a note of the number of turns when you rmove it.Take apart the fuel pump (18) and clean everything.Use compressed air on jets and fuel passages if possible and don't poke the jets with a wire as this could enlarge them.

 

[Topcat47]

Don't forget you can get cans of compressed air from hobby shops, you don't need a compressor for this. Failing that, a large puffer brush from a camera shop will do at a pinch. Carb cleaner and a lint-free cloth are great for removing all traces of sediment from the bowl, very important with current lead-free petrol.

 

[lustyd]

Thanks guys, would the carb cleaner spray be sufficient? This is just as powerful as any spray air I've had.
Cheers
Dave

 

[30boat]

Thanks guys, would the carb cleaner spray be sufficient? This is just as powerful as any spray air I've had.
Cheers
Dave

It depends on how much gummed up the carb is.Leave the parts to soak for a while to soften up any residues and give it a try.

 

[lw395]

The parts 17 to 24 look like a diaphragm fuel pump.
19 is a reed valve.
This area can usefully be cleaned or checked for debris.
The rubber diaphragm is oscillated by the crankcase vacuum to pump the fuel. Check it has no holes or splits.
Take care dismantling, it will be quite thin and fragile, and very possibly stuck to one or both sides.

Main thing will be the float chamber and jets 2 -5 as has been said.

I find it useful to dismantle carbs onto a sheet of white printer paper, keeps it clean and does not fall apart like kitchen roll, which is handy for cleaning stuff.
I try to do it outdoors due to the smell of petrol.
Wear polythene gloves if you can.

HTH.

 

[VicS]

I try to do it outdoors due to the smell of petrol.

Its impossible to find any bits you drop if you do it out doors

Seated at a decent table/ bench and work in a large tray if you can so that bits cannot escape,
Be sure to locate and identify any little gaskets as you dismantle it.

Watch out for the little spring clip #7 that links the needle valve to the float arm.

As said avoid poking jets with a wire that might damage them. I use a soft copper wire when necessary. Nylon mono filament can be used too

Also as said note how many turns the slow running adjustment screw is off its seat. that appears to be the only adjustment to tinker with when you have finished

 

[Lakesailor]

Number 3 and number 5 will be jets. They'll have a slot to unscrew them with.
Use a screwdriver that is a good fit (ie: big enough) and fairly new. Screwdriver blades that are worn will tend to slip or chew up the slot. It's only brass and damages easily.

 

[lw395]

Its impossible to find any bits you drop if you do it out doors

......

It's pretty hard to find anything you drop on my garage floor.
I think the spiders run off with bits.

 

[Davy_S]

Pay particular attention to No 2, it looks very similar to my jets, it has tiny holes down the sides.Buy good carb cleaner and soak the jets overnight, This is the best way to remove varnish deposits as the cleaner is a solvent (keep it away from seals and o rings)

 

[VicS]

Number 3 and number 5 will be jets. They'll have a slot to unscrew them with.
Use a screwdriver that is a good fit (ie: big enough) and fairly new. Screwdriver blades that are worn will tend to slip or chew up the slot. It's only brass and damages easily.

#3 and #4 are the jets # 5 is described as a "cap"

As Davy_S says also make sure the nozzle #2 is clean

 

[larson250]

I use an ultrasonic cleaner for jets etc. Fantastic bit of kit, you will be amazed how much rubish comes off/out the jets. Even when they look clean.

Larson250

 

[DaveS]

Its impossible to find any bits you drop if you do it out doors

Seated at a decent table/ bench and work in a large tray if you can so that bits cannot escape,
Be sure to locate and identify any little gaskets as you dismantle it.

Watch out for the little spring clip #7 that links the needle valve to the float arm.

As said avoid poking jets with a wire that might damage them. I use a soft copper wire when necessary. Nylon mono filament can be used too

Also as said note how many turns the slow running adjustment screw is off its seat. that appears to be the only adjustment to tinker with when you have finished

The kitchen table is the traditional place for dismantling carburettors. It's probably best if SWMBO is out...

 

[lustyd]

The kitchen table is the traditional place for dismantling carburettors. It's probably best if SWMBO is out...

As luck would have it SWMBO recently posed the "me or the boat" question and so is no longer with us