78 Johnson 150, Fuel problems?

[krosemond]

I was in the keys last week with my 1978 Robalo center console with a Johnson 150, and after taking on 30 gallons of gas, the engine started running very rough. The engine has provided years of good service (Dad bought the boat new in 78, and it sat for about 8 years, but has been recommissioned and run well for the last 5 years) until last week. At first it would barely run, it smoked and refused to idle. I changed the inline water separator/fuel filter and it was half full of water. It had not been changed for at least 4 years. I then change the spark plugs and used a can of OMC carb cleaner in the carbs while running. It immediately ran better, but would cut out and sputter at higher RPM's. I was able to salvage the vacation and run out about 60% of the fuel in the tank, and the sputtering got less frequent. I took it to the lake yesterday and it ran fine except for one short spell of sputtering in about one hour of high RPM (4000) running. I did add some new fuel to the mix. Are my problems going to work their way out, or there other things I should check?<br /><br />Also, at the very end of the day yesterday, when I put the throttle in forward, it clunked a little bit like it didn't want to go in gear. I suspect that is a separate linking problem, but don't want to rule out lower unit problems. Any suggestions?

 

[Dhadley]

Re: 78 Johnson 150, Fuel problems?

Sounds like you have got a handle on it. Probably just got a load of damp fuel down there. Unless the boat had been setting before you went. Either way you may want to consider cleaning the carbs. Make sure you got the correct plugs (Champion). I prefer to get rid of questionable fuel but if you think there is still water in the tank you could disconnect the line from the motor and use an electric fuel pump and cycle it back into the tank. Keep checking the water seperator filter until there is no more water.<br />Good luck!

 

[ODDD1]

Re: 78 Johnson 150, Fuel problems?

Dhadley, you got it.....sounds like a classic case of water in the gas.

 

[JB]

Re: 78 Johnson 150, Fuel problems?

IF the problem is contaminated fuel (sounds like it is) and IF the contamination is water only, try a bottle of HEET or similar water "remover" to 20 gallons of fuel. They don't remove the water, but they will make it mix with the gasoline and burn. This is a second choice if you don't want to or can't simply discard the problem fuel. Dhadley's suggextion is the bulletproof solution. Good luck.

<br />JB

 

[krosemond]

Re: 78 Johnson 150, Fuel problems?

Thanks for the replies guys. Glad to have found this group. I tried to syphon the gas out with no success, the tank is deep in the skiff's belly. I used to run my 24' topaz with a volvo diesel over to the Abacos quite a bit when I lived in Stuart, FL and had to change fuel filters quite a bit after fueling at out island marinas. But this was fuel I got at Holiday Isle in Islamorada, which is a busy marina. I wouldn't think they would have problems with the fuel, but who knows? The boat had been sitting since labor day in NC where I live now, but I ran it for about an hour at the lake before leaving for the keys, and for two days there before taking on this fuel and the problems began. I did check the new separator when we got back, poured the contents into a gatorade bottle and there was a trace of water in the bottom about the thickness of two quarters. <br /><br />When you suggested cleaning the carbs, does that mean taking them apart? After spraying the OMC carb cleaner in there, I got a real dirty black oily drip out of the exhaust. Any harm in repeating that process? This engine has run well (although I suspect it has less than 1000 hours) for 23 years with no repairs. I imagine things are fairly gunked up inside the engine. <br /><br />Thanks for the help, my only exposure to outboard mechanics has been, turn the key and go.