hard starting 1979 Evinrude 15 (15904e)

[billybuck1]

I pulled out my 15hp this spring. Started up and ran great for the day. A week later, wouldn't start. Pulled and cleaned carb. Got it started, would not reach high rpm as though on one cylinder. Did carburetor rebuild. Still hard starting and no top end. Gave to mechanic. Did compression check; good compression. Needed power pack. Achieved high end after power pack. Would not run without his pumping fuel line bulb at high speed, and smoking alot. Brought it home. Replaced both fuel lines under cowl, installed new fuel pump, runs great now once started but have to use starter fluid to get started, and if it sits for several hours, need starter fluid again, then runs beautifully once started. Thoughts on why I need the starter fluid??

 

[mikesea]

Re: hard starting 1979 Evinrude 15 (15904e)

the choke isnt working properly,a common mistake is ,putting the choke pull on backwards,or missing the slot it needs to slide into,if the choke pul is working OK,then ,the choke tube in the carb is likely plugged with gunk,with choke butterfly closed ,the suction of the pistons should pull raw fuel upward from the carb,starting fluid is not good to use,it breaks down any oil that is lubing the eng.your better to get an old windex bottle and put mixed oil/gas in it for those times you may need to prime

 

[AlTn]

Re: hard starting 1979 Evinrude 15 (15904e)

if you didn't remove the core plug on top of the carb and clean the well and 3 tiny holes leading from the well to the rear of the carb throat...you need to do so as these are the primary passage ways for the starting circuit when the choke plate is closed and the idle passage ways when at idle...if you did remove and clean...maybe a half turn rich on the mixture needle will give a better start

 

[billybuck1]

Re: hard starting 1979 Evinrude 15 (15904e)

Mikesea - The choke pull is properly connected and the butterfly plate does close. When you say "choke tube", are you referring to the tube dead center of the upper carb housing which reaches down into the bottom of the bowl? I ran a wire up that and blew carb cleaner through it, succesfully. Any better method?

AITn - if the core plug is the larger of the two "plugs" which come with the carb kit, I did replace it (I replaced both), but I do not recall any passageways under the plug. I thought the plugs simply sealed the voids left from casting the carb during its construction. Is the "well" under one of those knockout plugs? Can I get the plugs without buying another carb kit? I did not seal the plugs with lacquer or nail polish. Could that cause the choke not to draw?

Do either of you know of a schematic for this carb?

Thanks for your help. I do think the choke is the issue, though it idles very well once running.

 

[bktheking]

Re: hard starting 1979 Evinrude 15 (15904e)

These motors are hard to start unless the choke is staying fully closed while starting. Verify that the metal tang that holds the plastic choke lever in place is doing its job, after a while they need to be bent back in place to achieve a proper grip on that choke rod.

 

[billybuck1]

Re: hard starting 1979 Evinrude 15 (15904e)

bktheking - I left the plastic carb silencer off and can see the plate is closed. I'll check the tang as I know there is some play in the choke arm.

I did find a schematic. Looks like #5 is the core plug under which there are ports I gather I missed cleaning? I can't find a "choke tube" in the schematic. Does the high speed jet act as the choke tube when the butterfly is closed?

http://www.boats.net/parts/search/BRP/EVINRUDE/1979/15904E 1979/CARBURETOR AND MANIFOLD/parts.html#

 

[AlTn]

Re: hard starting 1979 Evinrude 15 (15904e)

yes..#5 is the plug I was referring to...under it, to the very rear, are 3 tiny holes that lead to the rear of the carb throat. I put the straw from an areosol spray can of carb cleaner directly on those holes and observed the spray pattern in the rear of the carb throat....I'd suggest holding the carb a ways out if you do this as that carb cleaner burns mightily if it gets into your eyes.

 

[billybuck1]

Re: hard starting 1979 Evinrude 15 (15904e)

Thanks AITn. I was able to get the Welch plug at the local marina, but then, of course, the engine started right up when i went up to pull the carb after sitting for a day and a half. Guess I'll try it daily for the next few days. Wonder if the fuel (no ethanol) in the carb may have lossened/liquified the blockage in those ports?