15 hp evinrude, will not run????

[mckeemm]

Hi Folks,

I have a 1987 Evinrude 15 hp 2 stroke outboard, late manufacture with the CD2 electronic ignition.

It will start and run and die. It will not sustain running for more than 20 seconds. I have the manual and I have completed the following.
1) compression check 120/120 psi
2) new spark plugs and wires
3) tested all ignition components that could be tested with an multihmeter according to the manual
4) repaired chaffed wires on trigger coil
5) tested fuel pump, fuel squirts out of the line at the carb when you pull the cord.
6) cleaned carb (3 times) installed OMC carb kit and replacement plastic top cover due to crack

I'm not sure where to go from here. The chaffed wires were grounding out and killing the ignition at one time and may have damaged the ignition power pack. To me the spark looks a bit weak (hard to see in daylight). However if spark was the problem, why does it start and run then die? It seams to be starved for fuel but why after 3 thurough cleanings and a complete carb rebuild does it not get enough fuel? I'm wondering about blown crank seals or broken reeds but I don't now how to test for that.

Any ideas?

Thanks, Mark

 

[nphilbro]

Re: 15 hp evinrude, will not run????

I had the '88 version of this and had the exact same problem.

Pull the carb back off and disassemble it. You'll see 3 very small jet holes in a line on the bottom of the main carb body. Take a piece of small copper wire (I use solid 24gauge solid telecom wire and it's soft so it won't change the jet size) and push it through them. Spray some more cleaner in there if you wish but probably not necessary. Carb cleaner and soaking alone doesn't clear these out. Reinstall and expect a good running motor.

Let us know how this goes.

 

[Solittle]

Re: 15 hp evinrude, will not run????

When it starts to die squeeze the primer bulb. That may help to point to the problem.

 

[mckeemm]

Re: 15 hp evinrude, will not run????

Thanks for the tips.

nphilbro,

I had the black plastic cover and gasket off again this afternoon. I checked to be sure we had the correct gasket and the three small holes that you can see under the cover were open when checked with a fine wire. Are their other ports that could be clogged?

Solittle,

I pumped the bulb when the engine starts and it made little difference. Maybe prolong the run time by a few seconds but moter still dies.

 

[the machinist]

Re: 15 hp evinrude, will not run????

Sinced your carb has the plastic top it is the late 87. Check to see if the plastic top is cracked at the idle screw location, or warped in the rear allowing air to sneak in.

 

[mckeemm]

Re: 15 hp evinrude, will not run????

Machinest,

Thanks, but as I stated in the original post I have already replaced the plastic top cover because it was cracked from someone over tightening the sholder screw that mounts the cam roller.

The motor is acting like it's starving for fuel. Myself and another person have both disassembled/cleaned and inspected the carb before reassembling. Last time we reassembled with the new top cover and complete carb kit. All visible ports and passages have been checked. The only thing I can think of to do is repeat the process of carb cleaning until we find whatever blockage is hiding in there. I have rebuilt many carburetors and never have I had such a dificult time to cure a fuel delivery problem. That's why I put the call out to the iboats community. I thought I must be missing something!

Thanks again, Mark

 

[Tim Frank]

Re: 15 hp evinrude, will not run????

Verify that there is not a problem with your fuel tank and/or fuel line by testing with a"known-good" tank and line.
Quick, easy, and worth the small amount of time to rule that out..

 

[mckeemm]

Re: 15 hp evinrude, will not run????

Tim,

We swapped the fuel tank and line for new units with the same result.

Went through the carb again and confirmed without a doubt that all passages were clear. The float and mixture screw have been adjusted to the manual specs. Reassembled with the same result.

We removed the prop so we could run the motor in a bucket at speed by putting it in gear to get past the throttle lock. We managed to get the motor to run for a longer period but it bucked and jumped, raced and generally was not happy. As soon as we reduced the throttle it quit.

Looking for more ideas?

Mark

 

[nwcove]

Re: 15 hp evinrude, will not run????

running the motor without the prop could solve your problem.....but not in a good way! it does seem like its running lean tho, what do the plugs look like after it quits?

 

[mckeemm]

Re: 15 hp evinrude, will not run????

nwcove,

Plugs look clean and dry. Starving for fuel is how it's acting. It doesn't get any at idle and pour or inconsistant flow at speed.

Is it possible that the crankcase is leaking preventing sufficient fuel/air mixture getting to the cylinders? What are the symtoms of blown crank seals? Could that cause this kind of a problem? Can I pressurize the crankcase to check for leakage at the seals? Maybe put a blanking plate at the carb flange and introduce some air at the vacuum port for the fuel pump.

Just thinking out loud.

Mark

 

[Rick.]

Re: 15 hp evinrude, will not run????

I'm having a similar problem with my 4 hp right now. I am rather certain (after much work and thought and help) my upper crankshaft seal is shot allowing very little gas into the carb. I can make it run by almost closing the choke shut, almost shut. The Machinist said to put some heavy gear oil on the top of the seal to see if that helps. Haven't tried it yet but I will soon. Trouble is it runs fine in my tank and like crap on the lake and I don't get out fishing nearly enough. Best of luck. Rick.

 

[nphilbro]

Re: 15 hp evinrude, will not run????

I'm pretty familiar with this motor so here some other things to try:

Try switching the plug wires around. I had a 9.9 that would sputter but not start so I reversed (1-2/2-1) the plug wires it fired right up.

Put the silencer back on and spray fuel AT the carburetor, including the bottom of the carb bowl and from each side (but don't hit the throat)- this may get a reaction, enough that vapor went through it - ie. crack or gasket problem. I've also used an unlit propane torch focused around the fuel system to isolate air leaks but it's a bit more difficult with only one person.

When the idle screw is "soft tight" bring it 3, then 4, then 5 turns to see what happens. The threads on some of these are finer then older ones.

Can you spray fuel into the carb throat to the point it will suck fuel out of the bowl?

 

[Tim Frank]

Re: 15 hp evinrude, will not run????

Does activating the choke just before it quits have any effect?

Have you tested spark with a proper tester, or did you just do the "lean the plug against block" thing? That is not a good enough way to test.

 

[mckeemm]

Re: 15 hp evinrude, will not run????

Thanks for the help gentlemen,

nphilbro,

We tried swapping the plug wires with no results. We knew it was a long shot but easy to test. We had already confirmed the wiring with the manual.

We did not have a spray bottle for fuel handy or a propane torch to test for vacuum leaks but we will try this as soon as we get a chance. I should have thought of this. I've done this before to check for vacuum leaks on vehicles.

Tim,

We checked for spark with the plugs grounded to the head and with a neon bulb type tester but not the perscribed tool which requires the spark to jump a 1/4" gap. I doubt this motor would do it. As I stated earlier we know that the wires for the power pack were damaged and grounding out. The spark appears weak to me. The manual is full of warnings about not shorting or sparking this powerpac so we decided to order a new one just to be sure. It will be here Thursday.

I'm working on this with a buddy so we may not get to this till the weekend now.

Thanks, Mark

 

[mckeemm]

Re: 15 hp evinrude, will not run????

Hello all,

Weak spark was the problem. My buddy received the new cdi unit and installed it this morning. He reports that the motor started right up and idled down nicely. It just needs a minor carb adjustment for idle mixture and we can go for a water test.

I have already invested in a fixed gap (1/4") spark tester. Neon bulb spark checkers and grounded plug tests are enough to tell you if you have spark but are not sufficient to indicate the quality of the spark. Obviously the cdi was failing to provide adequate spark to run this motor. Lesson learned.

Thanks for all your help.

Mark

 

[Rick.]

Re: 15 hp evinrude, will not run????

Good to hear you making progress. Hope she runs well on the water. You may need to richen the slow speed needle a we bit. Rick.

 

[the machinist]

Re: 15 hp evinrude, will not run????

The actual spark gap should be 7/16" to 1/2" for the electronic ignition & 1/4" for the magneto points & coil type

 

[bonzoscott]

Re: 15 hp evinrude, will not run????

Google Thexton (I think 505) spark tester. Adjustable I think to 1 inch, available at Napa. I've heard different numbers as to "How Much" in distance. Some say only 1/4 inch, but that tool will let you know where you stand. Used it on a standing Harley problem and get a barely visible spark at 3/8 inch.