1981/175 johnson

can anyone help the outboard runs really well in the tank and all day running.But come home and idle into port stop at the plontoon get car and the thing wont idle or run well enough to even get it on the trailer is this vaporizing or oil foil . if oil foul can i i run a hotter plug to try and stop this.The plugs dont seem too bad when checked

Re: 1981/175 johnson

Welcome widawake!<br /><br />I think the first thing I'd do would be to check the fuel supply line to the engine. Make sure the bulb will pump up tight and you don't have any leaks around the fuel pumps or carbs.<br /><br />Check the spark to each cylinder. Each spark should jump at least a 7/16" gap with a hot lighting like spark.<br /><br />Had any maint. done on it lately?

Re: 1981/175 johnson

I'm not sure I understand the situation when it's not running right. <br /><br />You come in and tie up to the dock and the motor is running fine. Shut off the outboard and go get the trailer. The trailer is in the water and then are you trying to drive the boat on the trailer and thats when the motor doesnt act right?

Re: 1981/175 johnson

Morning Mr. D. Up to watch the sunrise?

Re: 1981/175 johnson

Yep, I think so. Been up since 2 AM. Bummer.......

Re: 1981/175 johnson

Yes it is driving on the trailer.Mantance a lot new carb kits new fuel lines, stator, plug leads and water jaket overhoul.I even drained and cleaned the fuel tank, if this motor sits after a long run for more than about five minites it plays up until it completly cold.

Re: 1981/175 johnson

Had some trouble finding your thread widawake...<br /><br />What did the water jacket overhaul consist of....this a saltwater boat?<br /><br />What do you mean by "it plays up until it completly cold".

Re: 1981/175 johnson

I think what youre seeing is somewhat normal. It runs fine until you want to drive it on the trailer. Think about what happens as you go on the trailer. The bow comes up which means the stern goes down. When the stern goes down so does the motor. That creates additional backpressure which hurts acceleration. If it goes down far enough and covers the exhaust relief holes the motor will most likely stall.<br /><br />When you accelerate normally the water in the mid section drops out rapidly as the boat moves forward creating much less backpressure. Going on the trailer the boat isnt really moving fast enough to let the water out. Hence the backpressure stays there. The motor cant breathe properly and stalls.

Re: 1981/175 johnson

Thanks for that Dhadley any way to make it better it drives me nuts.OBJ deflectors thermostat water pump and head gaskets it is a v6 19881 175

Re: 1981/175 johnson

You're going to need to look at set up if it's strictly a problem driving it on the trailer. If it happens other than loading, then we have to look elsewhere.<br /><br />Go back and answer OBJ's question about it "plays up".<br /><br />Then tell us more about the boat and set up. What kind of boat? What's the top rpm? Jackplate?