Poor tick-over Yamaha malta o/b

[davidej]

I got my Malta out of winter storage yesterday for a pre-season test. It started easily, ran well and plenty of cooling water thru. However it wouldn't tick over, it just died as I tried to bring it down to low revs. It seemed quite smokey - I do't remember this problem last season.

Should I try to adjust the pilot screw - the brass one just above the butterfly spindle? I assume that alters the fuel mixture at low revs -I believe the main jet is fixed.
Does anyone know the factory default setting?

Any suggestions welcome.

 

[onesea]

I got my Malta out of winter storage yesterday for a pre-season test. It started easily, ran well and plenty of cooling water thru. However it wouldn't tick over, it just died as I tried to bring it down to low revs. It seemed quite smokey - I do't remember this problem last season.

Should I try to adjust the pilot screw - the brass one just above the butterfly spindle? I assume that alters the fuel mixture at low revs -I believe the main jet is fixed.
Does anyone know the factory default setting?

Any suggestions welcome.

My suggestion is leave the settings alone, if it worked well last year its probably fuel / spark related. Drain the bowl, blow into the carb any where you can, easily. Run it for 30mins - 1 hour, once the dirt is off the jets the engine should burn it easily. Also try changing the spark plug.

If that fails refresh the fuel, turn engine upside down and empty tank refill with freshly bought, try again.

If these methods fail try the suggestions below about tuning/ stripping the carb, replacing gaskets looking for fine air / fuel leaks. In my experience you leap into a whole world of fine tuning that is often not required, unless you start stripping it.

 

[VicS]

+ 1 for changing the plug if fresh fuel does not cure it

Many times problems described on these forums that suggest carb problems are cured with a new plug.

 

[Boathook]

Like others fresh fuel and a new spark plug.

 

[corinthmistral]

Just had similar with my mercury 4 two stroke. Drained and dumped the fuel (only a couple of litres hence didnt use it in anything else). Started first pull and ran perfectly. Unleaded "goes off" these days due to biofuel component etc and I have found on my outboard this is critical, even if fuel has sat for say 6 months. Strimmer is the same. 4 stroke engines and multi cylinder engines (e.g. my 2 stroke twin cylinder marine 25hp outboard) seem to be less critical and "old" fuel seems to be OK with them, albeitn a bit smokey and doesn't runs quite so smoothly.