Yamaha 60hp Fuel problem

[Dr Jizm]

Basically my 1996/1997 60hp is cutting out and refusing to restart after being run for a while. I was out and cruising along at about 25knots and I slowed down to stop and put it in neutral and it died and then refused to restart. Had to get towed in. Took it home and cleaned all the fuel system right thruogh and the carb main jets. All seemed ok running in a water bin in the garden. Took the boat out again today to check all is ok and it isn't. It did exactly the same. Fine for a while then cut out and died as soon as I stop for the first time. Now it starts and runs for a few sconds then dies again.all help much appeciated. Thanks

[JB]

Sounds like a vacuum lock in your fuel tank, Doc. Check the vent for a clog.Good luck, and welcome aboard.

[Dr Jizm]

Pretty sure it's not that, but will double check anyway. It seems to be when the engine gets up to temprature the fault appears. Could this problem be to do with the pilot jet? If I get the motor to start and then rev it it seems ok but when I go back to idle she dies and refuses to restart!PS: I have been a member for a couple of years nut changed my Pc and isp so lost all my old log in details!

[ianyoung77]

When it refuses to restart have you checked the spark and tried spraying blended fuel in the carby?

[Dr Jizm]

Ok I just cleaned the carbs out again this time made sure I did the pilot jet and all that. Now she starts lovely and revs lovely but will not idle for more than 30 secss without coughing and dying. It will then restart and do the same again.I am starting to pull my hair out now!!!

[douglloyd]

Sounds like you need to turn out the pilot jet screws. Go out one turn then if that works turn them in a quarter turn at a time until it quits again (give some time between each adjustment for the carb to catch up) then turn it out a quarter and you should have it. Warm motor at idle in gear in water.

[Dr Jizm]

OK. I have had the fuel pump off and checked the diaphragm, all ok. Did what bluebird said and still no difference. Check the spark plugs like ianyoung said and all seemed ok but I replaced them anyway, I started it up and it has just sat there at idle long enough to heat up the water in the bin it is in to the temperature of a hot bath! It did cut out after about 10-12mins of idling but started straight back up and idled again for a few minutes. Would the temperature of the water it is in affect it? Engine is now quite hot.Is it worth going out for another sea trial do you think?

[sherwindu]

Just a guess, but are you working with fresh fuel?If not, try changing out your fuel tank with freshstuff and see what happens. Fuel older than a fewmonths or even less without a stablizer treatmentcan go bad on you, causing erratic performance. Sherwin D.

[Dr Jizm]

Yes I have used fresh fuel,good point though. I am pretty sure the spark plugs have cured it but I won't know for sure until I do a sea trial. To be honest there is not much more to it. I have a yamaha motocrosser and that will run fine one day and not start the next, always the plug, just goes with no warning at all. I think the plugs may be fouling up though, anyone else had that?

[sherwindu]

Another thing to check is if your gas tank is venting properly. Check the squeeze bulb after theengine dies. If it is not firm, this may indicatea fuel feed problem. I would also suggest an inlinefuel filter from the tank with a glass viewing window, so you can see if gas is coming from the tank. It also protects the engine from dirty fuel.Use a 10 micron filter for this purpose.

[Dr Jizm]

thanks for your advice. Does anyone know the base pilot screw settings for the yamaha 60?

[ianyoung77]

I haven't got the book for 1996 but 1992-5 was 1 1/2 turns out if that is any help

[Dr Jizm]

thanks, much appreciated.

[Jan Z]

I just went through this with a new motor (40hp 4 stroke) and the cause is the ethanol based gasoline that california is switching to.The ethanol collects water and the water/ethanol will corrode your carbs and clog your jets.The fix was carb rebuild, different jets and a Raycor water/fuel seperator set up with a ten micron filter.

[Dr Jizm]

thanks, will look at that.