1979 85HP Evinrude runaway fast idle/rough idle sputtering spitting vomiting motor!

Familyguyboater

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Ok, 1st off Im new to boating but not too new to turning a wrench although its been many years. Got this boat 17' with 1979 85 hp evinrude bout a yaer ago, do not know history. It sat here ever since til wife said use it or lose it, so I pulled it out cleaned it up washed it waxed it put new gas in and it started and ran rough with a fast idle. Gambled and took it to the lake as is and it would hardly start and when it did would die with a clunk when out it gear (from too high an idle?). Finally, it started and when it clunked it didnt die but was slow and I eased the throttle up and soon we were skipping across the waves at at least 40+ mph! It ran for at least 45 min and would throttle down some and idle rough, and started surging without touching the throttle, so we went home. (also put new plugs in before we left home). Now it just runs too rough and dies real quick unless i push the key in to choke it which smoothes the idle out some. Also when i unplugged one plug wire it adles way down and ran smooth smooth but died under throttle. So far Ive gotten a new gas can with even more fresh high octane fuel/oil, found/fixed a couple fuel and vacuum leaks, spark tested all 4 cylinders all had blue spark at least 7/16 or more, compression tests 120/120/112/112. Some plugs were a little wet. Ive already gathered that ill need to put a new water pump/impeller inand gear lube, but when i was a mechanic i was a diesel mechanic so gas engines im not super familiar with and i see marine engines are even mpore different, so any help would be hreatly appreciated. The main pronlem is this fast runaway idle that has me scrambling to shut the engine off and the bad rough idle, and diein when put in gear, help!!!!!
 

Dhadley

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Feb 4, 2001
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16,978
Re: 1979 85HP Evinrude runaway fast idle/rough idle sputtering spitting vomiting moto

Number 1 on the "to do list" - lose the high test fuel. 87 octane is what you need. Next clean the carbs. Remember the carbs not only deliver fuel but oil too.
 

Benny1963

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Sep 17, 2006
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Re: 1979 85HP Evinrude runaway fast idle/rough idle sputtering spitting vomiting moto

carbs and dont forget the water pump ,may also want to spark test and link and sink
 

Familyguyboater

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Re: 1979 85HP Evinrude runaway fast idle/rough idle sputtering spitting vomiting moto

did the spark test, all ok there....will lose the high octane also. Just dont understand the runaway idle rpms shooting so high
 

tashasdaddy

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51,019
Re: 1979 85HP Evinrude runaway fast idle/rough idle sputtering spitting vomiting moto

you need an OEM Manual. the carbs need to be cleaned and reassembled with rebuild kits. from your finding you have a good base to work with. you then need to linc n sinc the motor, covered in manual, it is an easy step by step procedure, that coordinates the spark advance, and the carbs so they work together, you varying idle could be that the motor is getting varying amount of fuel, due to the dirty carbs. here are the basics of carb cleaning, this was written for a 2 cylinder, but the principle still applies, keep each carbs parts separate, and mark each carb where it goes.

http://forums.iboats.com/showthread.php?t=244013

http://www.iboats.com/Evinrude_Outb....392412--**********.330846245--view_id.439444
 

Familyguyboater

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Re: 1979 85HP Evinrude runaway fast idle/rough idle sputtering spitting vomiting moto

thanks for the info, im ordering a manual and carb kits.
 
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