5hp Evinrude (idle question)

[Guppy35]

Hi Guys,

 

I just bought a new motor (1970's 5hp evinrude) for trolling.  The guy i bought it from took very good care of it and i had started it up in a barrel a few times with no problems before taking it out on the lake for the first time.  This past weekend i took it out and it started up just fine and i ran it wide open for a minute or two to get it warmed up.  When i idled it down to trolling speed, after a few minutes at trolling speed it began to produce an oil cloud behind the motor and then stalled.  Tried to start the motor a few more times and got it started only to have it stall again.  It does have a lean / rich knob on the front which was set directly in the middle.  Should i try running it all the way on lean when idling at such low speeds?  The mixture for this model called for 24/1, should the mixture be increased (say 35/1 or something) when trolling or is it best to keep it at 24/1 and just adjust the lean / rich knob?  I have also heard some guys say that when idling at lower speeds you can increase the gap on the spark plugs to reduce the chance of fouling the plugs...Any suggestions would be greatly appreciated!!

 

Thanks,

Sean

[trenchfisherman]

i would start with a new plug and use it under your normal load that you want.  after a little while remove the plug and look at it...most likely in your case it will come out black and wet.  If that is the case you are extremely rich and I would lean it out a little.  You can also try a hotter plug but messing with the gap would probably make it run worse since it would take more energy to jump the bigger gap.   with this little motor pushing a bigger boat it is probably struggling to make enough power at low speeds and it never gets a chance to clean it self out at higher RPM's.  i have also heard that you can lean our a mixture a bit but i would rather mess with the carb adjustment first to see if you can fix it.  here is a link to pictures of plugs.  good luck!!!

 

http://modernvespa.com/pix/uploads/spark_plug_colour_810.jpg

Edited March 13, 2013 by trenchfisherman

[Guppy35]

Trenchfisherman,

 

Thank you for the info!  I will definitely give it a try and see what happens.

[fishkiller16]

I would mix it at 50 to 1 it wont hurt it. I had a 1974 9.9 hp johnson that I ran at 50 to 1 or even a lil higher. I also agree with a hotter plug but only 1 heat range hotter.Also with the water temps right now the cyclinder temp cant get up to a proper operating temp and will definitly cause a fouling problem untill the water temps come up some. There is a good chance that 5 hp doesnt have a thermostat in it either.

[Sk8man]

A few things come to mind  in addition to whats been said - 1) Try new plugs  if they weren't brand new,  and recheck the gap, 2) Was the fuel ethanol (water accumulates in it) gas? If so, put NEW non-ethanol fuel in your tank (at a marina?) and try it, That lean and rich mixture knob should be OK in the middle to start with until you identify other possible contributors. Check the fuel filter if it has one that is accessible to see if it is clogged. The mixture may have been too rich in terms of the 24 to 1 since it is a motor that has had some previous use I'd go with 40 to 1 as it is still in the ball park (esp. since you had that slick out back). If your gas line to the tank was old or stored for a long time it may have had old fuel or contaminated fuel in them that went to the motor and hasn't worked its way through the system. Try a new gas line. I'd do one thing at a time so you can see the results and hopefully identify the problem. If the engine sat for a long time the carburator may need to be cleaned by a competent mechanic. If the lean/rich mixture is set right you shouldn't have to mess with it much under normal conditions even when idling or slow trolling (but right now the temps are far from normal operating conditions).

[Guppy35]

This is all great information.  Thank you all for the input, i will work on it this weekend and see if i can get it working right.

[Has Been]

Get some red stabil or Lucas fuel treatment, mix it strong & run the heck out of it. Sounds to me as if there is some carb issue , The plugs that come in it should be the ones you use. Adjust lean screw. Some have a plastic sleve on them that spin, so make sure the screw is actually turning. I have taken the hose off where it goes into the motor &  filled it with the stabil & pumped thru and let set. Put a clear  inline fuel filter after the primer bulb ,before the motor so you can see gas.

 

  My 86  35 merc float ball had to be replaced because it was not made for the ethanol. The hoses & plastic parts of older motors are not made  to take the ethanol. Use pure if you can.

[Sk8man]

Use the special MARINE STABIL it is about $20 and covers about 320 gallons> It is triple strength compared with the red stuff.

[Guppy35]

So i made a few changes.  I put new spark plugs in, cleaned the gas tank and put new (ethanol free) gas in it, and changed the mixture to 50-1.  Pulled the cord twice and it started right up.  So Saturday morning my brother and i took it to Keuka to try it out.  Once again, pulled the cord a few times and it started right up.  So i opened it up a bit to let it warm up as we were heading out, and after about 45 seconds it started to die.  I got back to the motor before it died and pumped the ball thinking maybe it wasn't getting gas but the ball was still hard.  Anyways it stalled out and i went to pull start it again and i could barely even pull the cord, it was basically seized right up.  I'm assuming after reading the replies to this thread, that the water temperature is just too cold for the motor right now.  Saturday the surface temp was 32 degrees.

[Sk8man]

That could well be a major part of it. My old 1979 Evinrude 4 horse didn't like the real cold either but would run fine when it was above 40 or so outside with water temp in the high thirties. It repeatedly needed to be restarted and had idling problems but luckily my 35 Johnson ran fine and that was much before ethanol gas

 

Just happened to think - It could still be a bad fuel connector at the tank or fuel line end or something partially clogged in the fuel line itself etc. I'd still try a different fuel line and bulb to make sure that isn't it.

Edited March 18, 2013 by Sk8man

[Guppy35]

I actually put a new fuel line on it as soon as i bought the motor, i forgot to mention that earlier.  But that still doesn't mean that it couldn't be something with the fuel line connector either to the tank or the motor.  Doesn't hurt to check that out while i'm waiting for the water temp to warm up     

[Chas0218]

Use the special MARINE STABIL it is about $20 and covers about 320 gallons> It is triple strength compared with the red stuff.

I use this with every fill up even tho I rebuilt my carbs with Ethanol safe gaskets, and components.