Evinrude dies unless I'm idling or full throttle?

[Southeastboater]

Ok, a little background. I had a rough day on the water that caused a broken dwell link and a blown power pack on a 93 70hp Evinrude. Got those fixed and now the motor runs fine in neutral, but when I put it in reverse or forward it chokes and stalls. I found that if I shift from neutral into a higher throttle position to keep the rpms up that it will run fine without any problems. However, when I try to back down on the throttle to low position (forward & reverse) it will stall. I've been managing, but this makes it impossible to slowly approach a dock or trailer with any sort of control against wind or current. Also, I'm forced to push more wake than I should when in a no wake zone because I have to keep the rpms up or it will stall. The problem started immediately after the rough day that caused other problems mentioned earlier. I've checked and am getting good spark to all 3 cylinders. I also adjusted the idle screw to no avail. I'm hoping someone may have some ideas as to what could be causing the dead range in the lower rpms while in gear. Any input and suggestions are welcomed. Thanks.

 

[rickdb1boat]

Re: Evinrude dies unless I'm idling or full throttle?

Check the link from the timer base to the throttle arm (Unless that is what you are calling the dwell link). It may have popped loose. Check all the other linkage and throttle plates too..

 

[Southeastboater]

Re: Evinrude dies unless I'm idling or full throttle?

All the links appear to be working properly. Any idea why the motor will run fine at nuetral and WOT but stalls at lower rpms in gear?

 

[Lakester]

Re: Evinrude dies unless I'm idling or full throttle?

hello,
did u fix them or take it to the shop? almost sounds like a vacuum leak possibly?
regards
lakester

 

[kenmyfam]

Re: Evinrude dies unless I'm idling or full throttle?

All the links appear to be working properly. Any idea why the motor will run fine at nuetral and WOT but stalls at lower rpms in gear?

Well in neutral you are not putting any real load on your motor and at WOT you are throwing so much fuel and air in there that it keeps going. Even though it keeps running it does not mean that it is running correctly at WOT. Have you done a compression check ?? that will tell a lot about the health of your motor before going any further.
Sounds to me like there is a timing issue with your motor. Have you done a link and synch ??
A lot of folk with more knowledgr and experience than me out here that will be along to help shortly. Just my 2 cents for you to ponder.
Good Luck and post the root cause when you have found and fixed it so we can all learn from it.

 

[Southeastboater]

Re: Evinrude dies unless I'm idling or full throttle?

Thanks all for the responses. I did replace the plugs, power pack and the broken link myself with the help of someone who is a little more knowlegable about motors than me. I'm now planning to take it to a local marine mechanic to find and fix the stalling problem. I bought this motor back in April and haven't done any type of work on it except the items mentioned above. After reading many of the other motor issues/remedies on this forum, I have a hunch (my novice opinion that may be way off) that the rough day out has caused a timing issue since that is when all of my problems started. I would still welcome all ideas and suggestions from anyone so I can mention them to the mechanic. When this is finally resolved, I'll be sure to post the fix.

 

[HighTrim]

Re: Evinrude dies unless I'm idling or full throttle?

I think you should start with ensuring that your idle is set to 650 under load and in gear. (On the water) I would then perform a link n sync, and check all throttle settings including timing (see Joe Reeves intstructions in the FAQ). When were the carbs last rebuilt? May be time for a bath and rebuild. Check to see if the timer base (starboard side, under the edge of the flywheel, linked to the throttle lever) moves smoothly without sticking when you advance the throttle.

Take the airbox cover off & observe whether the throttle plates are parallel.

Also, the timer base should start it's travel *before* the throttle plates start to open, else she'll fall flat when you try to accelerate.

 

[flabum]

Re: Evinrude dies unless I'm idling or full throttle?

Is it running up to full throttle? Does it run smooth above idle? If not, check that you put the primary coil wires in the right position: There are two wires with stripes on them and one without.....the blue stripe goes to the top cylinder, the green stripe goes to the bottom and the one with no stripe goes to the middle.

 

[Southeastboater]

Re: Evinrude dies unless I'm idling or full throttle?

Thanks for the responses. I hope it's something simple like a cleaning and adjustment that is needed. I don't know when the carbs were last rebuilt, but they probably could use some attention. The wires are connected in the same order as they were before I replaced any parts and it does run smoothly in gear as long as I keep the rpms up to at least 2200 rpms. Any less and it stalls unless it's in neutral. I'm taking it to a mechanic after the holidays since I've exhausted my patience with it (translation: I'm not that much of a mechanic.) I'll post the fix when it's running properly. Thanks again.

 

[rockyrude]

Re: Evinrude dies unless I'm idling or full throttle?

I've learned that carbon is killer on two strokes. If your exhaust ports ( amongst other places) get carboned (sp) up it won't breath correctly. Keeping it above 2200 only provides enough force to just blow it through.

 

[Southeastboater]

Re: Evinrude dies unless I'm idling or full throttle?

PROBLEM SOLVED - OK, it's been a while, but I finally got the motor to a mechanic and it's now fixed. He cleaned the carbs and set everything back to factory specs, but that didn't solve the problem. He checked the compression of all 3 cylinders and noticed that the bottom cylinder was a couple of psi lower than the other two. He checked the plugs, but didn't see anything that would suggest the bottom cylinder being the problem, but decided to check the gasket on it anyway. BINGO, bad gasket. Not too bad, but bad enough to cause it to stall under load while in gear. He said that putting enough throttle was causing it to force past the issue with the gasket and that's why I could run at 2200 rpms and faster. He replaced the gasket and the problem disappeared. Thanks to everyone who posted their ideas. Now I'm a happy boater again!

 

[72SideWinderSS]

Re: Evinrude dies unless I'm idling or full throttle?

Happy to hear all is well.

Thanx for updating the post with the solution, so many do not even bother.

Have a Happy and Safe boating season.

 

[BigNiner19]

Re: Evinrude dies unless I'm idling or full throttle?

VACUUM LEAK! Dang 2 strokes!