Hard Start '79 100hp

[zibzer]

Hello,

I have a 1979 Evinrude 100HP and when it is cold it is very hard to start once its running in runs like a champ but the initial start is very hard., and then when it DOES start it shoots out a lot of smoke and idles slow for a few seconds then kicks up to normal. Sometimes it seems i have to run through 1/4 battery to start it.

If i stop out on the lake and fish for a few hours it will start up okay (not great) , it just seems to be right when i launch it that it gives me problems... any help would be much appreciated.

BTW i just boat the motor this season and it has been like this since i first bought it. Also i mix the oil/gas in the main tank on the boat so i would assume it mixes well while im driving down the road... or maybe it doesnt mix well?

 

[jtexas]

Re: Hard Start '79 100hp

ya, the fuel/oil is plenty mixed by the time you get to the lake, no problem there. and the smoke is normal. sometimes more than others, I think (pure speculation on my part) its dependent on ambient temp, fuel temp, time since last shut down, yada yada yada.

most common cause of hard cold start: operator error.

Is this your cold start procedure?
Pump primer bulb until firm.
Raise hi-idle lever to full up position.
Push key in to choke and continue holding it in while turning to "start".
Release key when the engine starts, and back off on the hi-idle lever, leaving it up only as necessary to keep the engine running.
If the engine starts to die before she's warm, punching the choke will usually keep her from dying.

If that's what you're doing, then take the airbox cover off and check to see if all the choke plates are closing completely when the choke is activated.

If that checks out ok, do a spark test - spark should jump a 7/16" gap while cranking. It's possible the battery isn't delivering enough power or for some reason the starter motor isn't turning the flywheel fast enough to crank a cold engine.

A compression test might also be helpful.

What spark plugs are you running, and how old are they? Checked the gap lately?

let us know how it turns out.

oh, almost forgot - on a warm start, if she doesn't start up on the first bump of the key, raise the hi-idle lever a quarter or half-way for the 2nd try.....

 

[zibzer]

Re: Hard Start '79 100hp

thank you for the tips. That is exactly how i do my startuop procedure.. I will check the choke plates tonight. One thing i noticed last night when i was playing with it, if i press the bulb to get it hard it starts leaking oil on the fitting just after the bulb. I checked it out and the gear clamp was partialy broken and wasnt holding well. I will pick up a new clamp on the way home from work and see if that makes a difference.

spark plugs are a few months old and gapped. The coil packs maybe should be replaced even if they arent bad its probably good preventative maintenence for an old motor.

And i always start my engien (when warm) with the warm up lever all the way up or 3/4 up. If i do it with it off completely she gives me a hard time.

 

[jtexas]

Re: Hard Start '79 100hp

Obviously need to stop the leak, but unlikely that'll resolve your cold start problems - should be plenty of gas in the carb bowls after you prime the line.

If you have good spark & compression, sounds like time for a carb rebuild.

...
And i always start my engien (when warm) with the warm up lever all the way up or 3/4 up. If i do it with it off completely she gives me a hard time.

a lot of times a carb rebuild will resolve this, too - float valves/seats get worn, little bit of fuel leaks into the cylinders, you have a slightly flooded condition for your warm starts.

also, check out the engine FAQ section, the "DE-CARB" thread, some good stuff in there.