Motor ID :and wont run at low idle

[Jeff Goldberg]

Johnson Sea Horse 5HP what year?numbers on motor 935215/TN-28.Also will start with throttle on high and in gear but wont idle.Motor has to be in gear for throttle to be on high.When I move the throttle to the start position and take it out of gear it wont even fire.What shouled the comprerssion be on this motor. Any idea's.

 

[OBJ]

Re: Motor ID :and wont run at low idle

Welcome to iboats Jeff!<br /><br />You got a 5hp 1953 Johnny there.<br /><br />Compression....the higher the better. But more important, both cylinders should read within 10 to 15% of each other.<br /><br />Sounds what you need to do is get a carb kit and overhaul the carb. Sounds like you just aquired the engine?? Or it's been setting for a long time.<br /><br />Generally speaking, some other "stuff" you should be looking at are:<br /><br />Spark...each cylinder should have a hot white spark across a gap of 7/16".<br /><br />Water pump impeller...if you don't know when the last time it was changed out, you should do so.<br /><br />But...for now...here is a little something to try...count the number of turns it takes to run the low speed needle all the way in until GENTLY seated. Then back out 1/2 to 3/4 turns. Do the same with the high speed needle only back it out 1/2 turn and try starting again.<br /><br />If this dosen't get ya' running, overhaul the carb.<br /><br />Finally....if ya' don't have a service manual, get one if your serious about this engine. Iboats have the generics...see bottom of page. You can also get reprints of the original OEM service manual...which is preferred...from any of the links below.<br /><br /> http://www.marineengine.com/manuals/evinrude/order_pre-1980.html <br /><br /> http://ww3.kencook.com/evinrudejohnsonmanuals/ <br /><br />Keep us posted if ya' have any other questions...thanks.

 

[Jeff Goldberg]

Re: Motor ID :and wont run at low idle

Little history on this motor. I was at the dump one day and there it was in the metal bin. It's such a pretty little motor.I could'nt believe somone would throw it out.A little banged up but very clean.I have a Clymer 1.5-125 HP 1956 1972 shop manual. Guess I need to get another now I know what year it is.It seems to be pumping water from a small hole in a fitting on the left side of the motor facing the back of the motor pretty steady stream,does that sound right? I know about the compressin being close in both cylinders.But what should I see.In my 1963 75 HP I have 110PSI average.Gap for plugs?I pulled them and there wide open.More than .030.There is a Rich/Lean knob on the top also used for priming and another needle valve down below.And a gas shut off on the side i think.Which one is the high and low adjustments.Are rebuild kits for this motors carb still available? Thanks so much for your input.

 

[G DANE]

Re: Motor ID :and wont run at low idle

Most of these points should be set to open 0.020 at the "set"mark on cam if there is one, or at highest. Your luckey, I,v always dremt of owning one of theese, but they are rare here in Denmark. I dont think you have serious compression problems, you probably couldnt get it started, then. I would start at cleaning and setting pionts right and clean carb, including a good soaking and blowing thru with compressed air. Pay attention to the small gaskets around high/low speed needle valve, they must be tightened just enough to ensure it isnt pulling air instead of fuel. Must be removed before soaking in carb cleaner, with all gaskets and floater. Also as OBJ says, dont use any force on any of the needle valves, can ruin needne or seat. Good luck with this baby !

 

[G DANE]

Re: Motor ID :and wont run at low idle

Oh, the upper needle valve is low speed and the lower is high speed.

 

[Jeff Goldberg]

Re: Motor ID :and wont run at low idle

Just found out the coil for the top cylinder isnt firing. No spark. Bottom one has great spark.Guess Ill have to get a local guy involved.Compression is around 70 PSI on both.Wish me luck. Thanks again for the input.