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1987 48 spl idling issue

L

lposa

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I have a 1987 Evinrude 48 spl that does not idle well . I have rebuilt the carbs, replaced spark plugs, and replaced the fuel tank and hose. It runs well at mid range and high end. This problem has been going on for several seasons. I have been told to replace all fuel and the 2 vacuum lines going to the carbs, and also that it might be the primer selenoid assy. Any thoughts?
 
could the primer solenoid be leaking or malfunctioning if there is no visible signs of leakage of fuel? When I start the motor the idle will fluctuate and speed up or the motor will die.
 
Perhaps you do not understand that leakage on the primer solenoid could be internal and you would not see this.------Have you taken the time to do a compression test ?
 
when I purchased the boat from a Marina several years ago it idled poorly just as it does now. They tested the compression at that time and said it was good. I have tolerated the problem ever since, and have not retested the compression, but have tried other things such as rebuilding carbs. So I have assumed compression is good. I will retest.
I thought as you mentioned that the leakage would be internal on the solenoid. Thanks! If compression is good, would
you then be replacing solenoid or fuel lines?
 
I have the same motor and it had a bad idle too. Long story short, had a weak spark, would only jump 3/8 gap on spark tester, found charge coil under flywheel leaked black goo out, replaced coil, note: coil problem related to another problem,, but when changed, engine idled like a new motor.
good thing though, on the 48 spl it has a seperate stator and charge coil, much cheaper then all-in-one unit.

about your compression, i have 148 and 148,(i think i'm lucky with those numbers) if you try a SEAFOAM treatment it might even then out and maybe increase them, not say'n there bad but it could help
 
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Thanks for the input. I will get a spark tester and check the spark next as you did. Do you feel my compression numbers would have any bearing on the idle problem?
 
I'm not that experienced as several guys on this forum, but think if numbers were be low 100, maybe, compression and spark are the key things to start with
check the resent post about the 1989 GT 150 V6, kimcrwbr1 posts about the Seafoam treatment
what ever happens let us know the end results
 
thanks for the input. I purchased a spark tester and did the spark test this weekend. Both cylinders produced good spark at 7/16 gap on the tester. So I think that I can rule out the ignition. I will read the recent post you recommend. Take care.
 
any luck finding the problem, primer solenoids red handle should be in line with body, turning idle screw 1/2 turn in, advances timing a little and could help, do you have a tach?
 
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