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TOPIC: Problem 2 - tough cold start and rough idle

Problem 2 - tough cold start and rough idle 1 year 9 months ago #124323

  • Merccooper
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So, here is my second problem with my Johnson!

I've been having troubles with cold starts. If I let the starter run for, say about a minute to minute and half, the engine will very slowly come to life and putter until it continues to run almost normally (but rough idle). If I instead (in the same scenario with a cold start) give it one quick spray of quick start, it starts right up and runs almost normally (but rough idle).

I was thinking fuel pump. Any thoughts?

2000 Johnson 30hp, model number J30EVLSIA

Thanks
Tim

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124332

  • ed-mc
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Your engine is actually a 2001 model, according to the info at www.marineengine.com

The fuel system has a primer, is yours working?

Since this motor uses a primer instead of choke shutter, if the primer is not working you'll have a very difficult start. Hence the shot of starting fluid.

Which BTW, is not a good idea unless you are using the type that also contains lubricating oil. Otherwise the straight spray has no lubricating value and continued use will damage the powerhead internals.

It's not a good practice to operate the electric starter that long as it can overheat/burn out and/or damage the battery. Best to crank for 10-15 seconds at most then wait at least 30 seconds before cranking again, to give the starter a chance to cool down.

You should be able to hear the primer solenoid click when you push-in the ign key to "choke". Note that the primer only passes fuel when the key is pushed-in, so you have to keep it pushed-in while cranking. The initial shot of fuel comes from how hard you've pumped up the fuel hose primer bulb, so be sure it's firm before attempting a start.

Last thing, a hard start/rough idle could be caused by a too-lean idle mixture adjustment. You can adjust the needle for smooth operation with the engine warmed up and idling in gear. Set the needle to the "rich" side of the range of adjustment.

Here are a couple of parts diagrams of the offending bits:

www.marineengine.com/parts/johnson-evinrude-parts.php?year=2001&hp=30&model=J30EVLSIA&manufacturer=Johnson§ion=Intake+Manifold

www.marineengine.com/parts/johnson-evinrude-parts.php?year=2001&hp=30&model=J30EVLSIA&manufacturer=Johnson§ion=Carburetor+-+30

Worst case, you could mix up a small spray bottle of pre-mix and it should fire right off with that.

HTH............ed

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124343

1st, as stated above, the motor is a 2001. Has nothing to do with your problem, just an observation.

Now regarding the following which I have copied from above:

You should be able to hear the primer solenoid click when you push-in the ign key to "choke". Note that the primer only passes fuel when the key is pushed-in, so you have to keep it pushed-in while cranking. The initial shot of fuel comes from how hard you've pumped up the fuel hose primer bulb, so be sure it's firm before attempting a start.

The bold part is not correct. The primer solenoid gives one squirt each time you press the key in. It does NOT continuously squirt fuel regardless if you hold the key in or not. The best procedure is as stated above, pump the bulb hard 1st or you won't have fuel pressure at the primer. Then with the key on prior to cranking, press the key in 3 or 4 times. This will give 3 or 4 squirts before cranking. Then crank the motor. You may need to give it a few more pushes as it warms up.

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124347

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jimandros wrote:

The bold part is not correct. The primer solenoid gives one squirt each time you press the key in. It does NOT continuously squirt fuel regardless if you hold the key in or not.


I'm not understanding that description. The primer is a solenoid, it is either energized or not.

When energized, it passes fuel (when there is pressure in the lines, either from pumping the primer bulb or from the fuel pump when the engine is cranking). When deenergized, it stops.

So I'm not getting how it'll only squirt once when energized. What it should do is squirt fuel every time it's energized, and continue to squirt fuel until deenergized. There's no automatic mechanism that stops it from squirting after a specific time period of being energized.

Here's the best description I could find at another boating forum of how it works:

With pressure in the line the primer will squirt fuel even if the motor isn't cranking over. The solenoid is an electric valve. Activating the solenoid allows the pressure to be released. If the pressure was created by pumping the bulb the motor does not have to be turning over.

With the motor running the fuel pump is creating constant pressure (hopefully) and the primer will release fuel any time it's activated.


If you have a different technical analysis of how it operates, would be happy to hear it.

Cheers.......ed

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124348

  • Merccooper
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Thanks guys for the detailed input.

A couple of notes regarding the points you guys noted.

I've never been able to pump the bulb until hard. I guess that is something I have to look into.

I've never had to use the choke to start, even when cold it use to start up within 10-15 seconds. The issue with the cold start is relatively new.

Also with regards to the choke, i didn't even know it existed until about 2 months ago.....and I've had the motor for 6 years now :blink: But, I did try it since having troubles with the cold start but have not heard the "click" mentioned. Maybe with the cowling on it it is hard to hear?

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124358

Odly enough, I had a fouled plug in one of my cylinders that made my rude run like that. Found the problem by accident, reremoving the plugs to see if the cylinders were getting even compression. One never knows.

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124359

ed-mc wrote:

jimandros wrote:

The bold part is not correct. The primer solenoid gives one squirt each time you press the key in. It does NOT continuously squirt fuel regardless if you hold the key in or not.


I'm not understanding that description. The primer is a solenoid, it is either energized or not.

When energized, it passes fuel (when there is pressure in the lines, either from pumping the primer bulb or from the fuel pump when the engine is cranking). When deenergized, it stops.

So I'm not getting how it'll only squirt once when energized. What it should do is squirt fuel every time it's energized, and continue to squirt fuel until deenergized. There's no automatic mechanism that stops it from squirting after a specific time period of being energized.

Here's the best description I could find at another boating forum of how it works:

With pressure in the line the primer will squirt fuel even if the motor isn't cranking over. The solenoid is an electric valve. Activating the solenoid allows the pressure to be released. If the pressure was created by pumping the bulb the motor does not have to be turning over.

With the motor running the fuel pump is creating constant pressure (hopefully) and the primer will release fuel any time it's activated.


If you have a different technical analysis of how it operates, would be happy to hear it.

Cheers.......ed

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Re: Problem 2 - tough cold start and rough idle 1 year 9 months ago #124361

ed-mc wrote:

jimandros wrote:

The bold part is not correct. The primer solenoid gives one squirt each time you press the key in. It does NOT continuously squirt fuel regardless if you hold the key in or not.


I'm not understanding that description. The primer is a solenoid, it is either energized or not.

When energized, it passes fuel (when there is pressure in the lines, either from pumping the primer bulb or from the fuel pump when the engine is cranking). When deenergized, it stops.

So I'm not getting how it'll only squirt once when energized. What it should do is squirt fuel every time it's energized, and continue to squirt fuel until deenergized. There's no automatic mechanism that stops it from squirting after a specific time period of being energized.

Here's the best description I could find at another boating forum of how it works:

With pressure in the line the primer will squirt fuel even if the motor isn't cranking over. The solenoid is an electric valve. Activating the solenoid allows the pressure to be released. If the pressure was created by pumping the bulb the motor does not have to be turning over.

With the motor running the fuel pump is creating constant pressure (hopefully) and the primer will release fuel any time it's activated.


If you have a different technical analysis of how it operates, would be happy to hear it.

Cheers.......ed


You are correct, it is a solenoid & it will prime without the starter being engaged BUT the key must be in the ignition ON position. Once it has pulled in & the plunger stops moving, fuel flow will diminish. Operating it again will cause another squirt. It certainly isn't worth getting into a argument over the exact sequence. And it won't take a huge amount of effort to try what I recommend.

If the solenoid (or switch/wiring) has failed, it is possible to prime the motor by opening the bypass lever & squeezing the fuel bulb.

Regarding priming the bulb until it gets hard: Hold the bulb upright with the outlet up & try. Bet it works then.

I would check the compression and hope for 100 PSI min with the throttle held open. If it is OK, check the reeds. Low compression & broken reeds cause low speed issues more than high end issues.

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