1988 Evinrude 140 V4 - Crank seal

[lexer440]

This motor runs really rough between idle and 1500 rpm and someone suggested that a bad crank seal would cause that, (news to me). Changing it as you guys know is not a 5 minute job so I was wondering how can i test it to decide if it should be changed? My manual tells me how to remove and refit but nothing about condition or testing. My compression readings are between 116 - 120 across all four cyls and i was of the opinion that a rebuild was not needed yet.

 

[Solittle]

Re: 1988 Evinrude 140 V4 - Crank seal

Before you go opening that sucker up troubleshoot the fuel & electrical system. I'd be a bit skepticalabout what "someone said" without troubleshooting. Kinda amounts to guessing.

 

[Faztbullet]

Re: 1988 Evinrude 140 V4 - Crank seal

The small bore loopers was not a good idling motor when new. Check the recirculating valves for blockage and if idle and intermediate jets has been swapped. Also check to see that its running at temp as if to cold will cause idle problems.

 

[lexer440]

Re: 1988 Evinrude 140 V4 - Crank seal

Exactly, guesswork is an expensive way to troubleshoot anything hence the question. I have a bright blue spark on all four and sync & link is spot on, I am leaning toward air leak between tank and carbs but have yet to find the time to determine truth of that. A side note on sync & link, book says 8 deg ATDC which it is but i found if I set it to 4 deg ATDC it ran much better does that give any clues? I set it to 8 deg as it should be because I wanted it to be right, when I finally get the culprit it should run great.

 

[lexer440]

Re: 1988 Evinrude 140 V4 - Crank seal

Good points. jets were a mix of all the wrong ones, all replaced with new ones. Original temp tests were low, new thermostats have sorted that and operating temp is good and in spec. will check recirc valves.

 

[clanton]

Re: 1988 Evinrude 140 V4 - Crank seal

I think this motor has Quick Start which advances the timing about 6 degrees on startup, which increases rpms to 1100 at idle until warm. Motor should be at operating temps when checking or setting the timing. Idle timing should be set to spec, then link and sync. Final idle done by adjusting the idle timing screw, idle timing should be within +- 2 degrees of specs, after adjusting complete.