Merc V6 Carb - Fuel leaking out and primer bulb soft?

[Superjetjim]

Hi,

I have fuel pouring out of the botton left carb opening whilst running or shortly after stopping - Also the fuel bulb doesnt go hard anymore when priming - have I popped a check valve in the fuel pump?

The engine is also lumpy at tick over or just above since this started happening -seems a bit lazy out of the hole, but once it picked up it runs clean and strong. I'll pull the carbs and strip tonight, just wondering what to look for.

Compression is good/equal in all pots.

How do you check if a needle and seat are worn?

Thanks to everyone for any help!

Jim

 

[j_martin]

Re: Merc V6 Carb - Fuel leaking out and primer bulb soft?

Got under the bonnet, did ya. Where ya from.

look for sunk float, dirt and crud in the needle and seat, bad gaskets, loose float bowl screws.

Don't even bother opening it up till you have a gasket kit for it. Not much money, and they don't reseal gracefully.

hope it helps
John

 

[Superjetjim]

Re: Merc V6 Carb - Fuel leaking out and primer bulb soft?

Got under the bonnet, did ya. Where ya from.

look for sunk float, dirt and crud in the needle and seat, bad gaskets, loose float bowl screws.

Don't even bother opening it up till you have a gasket kit for it. Not much money, and they don't reseal gracefully.

hope it helps
John

Hi John,

Yes started poking around - looks similar to the Jetski engines I've tinkered with in the past (Yamaha) I've laso fitted a new wiring loom, control box etc

I'm from England and the boat is a Picton 185GTS.

Will strip them down tonight, carbs are off the block now, dont think they've ever been off before. Must be full of crap/varnish.. The engine starts to harden off after 30 seconds of WOT which indicates a restrictive/part blocked carb in my experience..

Carb gasket kits on order, along with a fuel pump rebuild kit including diaphragm. Where do the check valves come from (are they in the carb rebuild kit? - Any idea on the P/N if not?)

Thanks

 

[j_martin]

Re: Merc V6 Carb - Fuel leaking out and primer bulb soft?

Valving in the fuel system.

In the fuel pump, 2 disk valves. New ones are a clear plastic. Older ones are rubber, and probably warped by now.

In the primer bulb, an inlet and outlet check valve.

In the fuel bleed lines, one at the reed plate end of each. Easy to check when the carbs are off.

WOT symptoms are those of lazy or failing fuel delivery. Sleeper items are the fuel filter, and the bayonet fuel connector. If it's been replaced with plastic, it does not have enough bore to support this engine.

Keep track of which carb goes where, and also jet location. Sometimes they vary a bit from cylinder (pot) to cylinder.

hope it helps
John

 

[Superjetjim]

Re: Merc V6 Carb - Fuel leaking out and primer bulb soft?

Valving in the fuel system.

In the fuel pump, 2 disk valves. New ones are a clear plastic. Older ones are rubber, and probably warped by now.

In the primer bulb, an inlet and outlet check valve.

In the fuel bleed lines, one at the reed plate end of each. Easy to check when the carbs are off.

WOT symptoms are those of lazy or failing fuel delivery. Sleeper items are the fuel filter, and the bayonet fuel connector. If it's been replaced with plastic, it does not have enough bore to support this engine.

Keep track of which carb goes where, and also jet location. Sometimes they vary a bit from cylinder (pot) to cylinder.

hope it helps
John

Thanks Jon, are all the items required to rebuild the fuel pump included in the kit (P/N 89031A2) on below link:

http://www.outboardspares.net/acatalog/Fuel_Pump_Repair_Kits.html

Cant seem to see the check valves in there?

 

[Superjetjim]

Problem sorted - Merc V6 Carb - Fuel leaking out and primer bulb soft?

Problem sorted - Merc V6 Carb - Fuel leaking out and primer bulb soft?

John,

Thanks for your help - all sorted, it was the left hand carb float stuck open on the bottom bank. Stripped and rebuilt all the carbs - (super easy if anyones thinking about doing it) Also found a blocked high end jet on top right carb. So all carbs rebuilt now, also rebuilt the fuel pump along with new check valves/gaskets/O'rings. Purrs like a kitten now and starts on the button. Misfire gone caused by stuck float as well!

Water testing tomorrow so wish me luck!

Thanks again

Jim