1979 Evinrude 55hp throttle issue?

[trackerdave]

Engine will idle great and rev to full power when 'warm up' is lifted. The problem occurs when engaged in gear. She will run up to about 25% power perfectly but if I increase the throttle she'll sputter and die (if I don't back off). I thought the problem lay in the carbs so I rebuilt them with no change. I've been tinkering with the throttle adjustments but just can't seem to get it right. I was wondering if anyone knows what could cause the engine to sputter out when throttle is increased?, not getting enough fuel?, too much fuel? Any and all suggestions would be greatly appreciated. If it matters, the engine is powering a 24ft party barge. Thanks in advance.<br /><br />trackerdave

 

[Dhadley]

Re: 1979 Evinrude 55hp throttle issue?

When you advance the throttle, is the timer base under the flywheel moving?

 

[trackerdave]

Re: 1979 Evinrude 55hp throttle issue?

As a novice re-building the carbs was quite a leap. Could you explain a little more what the timer base looks like/does, I might be able to answer your question. I don't think I've taken the flywheel off yet. I do have the manual for the engine so if you believe this might be the cause I'll definitely check it out. Thanks for the prompt reply.

 

[wreckless]

Re: 1979 Evinrude 55hp throttle issue?

Did you clean all the orifices really good when you rebuilt the carbs? Sounds like you still have a gas/carb issue.

 

[trackerdave]

Re: 1979 Evinrude 55hp throttle issue?

Completely clean, soaked, scrubbed, and rebuilt. It actually wasn't bad and looked as though someone had re-built them recently (I just got the boat last year and haven't had much time at the lake to work on it).

 

[Silvertip]

Re: 1979 Evinrude 55hp throttle issue?

It's generally not the surfaces you can see that cause the problems. It's the small passages and jets that gather varnish and debris. Those need to be cleaned and blown out with compressed air. If you don't know if you've taken the flywheel off, you haven't. Its the big round thing at the top of the engine. Can't miss it. The timer base has a lever that sticks down from under the flywheel and moves in conjunction with the throttle. Remember, an engine with no load will rev high running on half its cylinders. Did you adjust the idle mixture screws with the engine running on muffs? If so, you need to do it in the water as there is no back pressure on muffs. Since the carbs were removed you also need to do a link & sync which makes sure the carbs and ignition timing advance in sync. This procedure is far too detailed to go into here so you need to either buy a service manual for your engine or visit the library. You can generally check out service manuals for two weeks.

 

[trackerdave]

Re: 1979 Evinrude 55hp throttle issue?

I do have the service manual and will look into the link and sync. Any suggestions on what it would be listed under? Engine timing? <br /><br />I've pulled the carbs back off and will go through them again and blow them out as well. <br /><br />Still curious why the engine will run great in 'N' but bogs down and dies when throttled up. I'll be reading up on the manual for the next few days but keep any suggestions coming and I'll try them all out. Thanks for all the responses.

 

[Joe Reeves]

Re: 1979 Evinrude 55hp throttle issue?

There are fixed brass high speed jets in the bottom center area of the float chambers, in back of that screw you see at the bottom front of the float chambers. Soaking at times doesn't clean them thoroughly, in which case it's a good idea to clean them manually with a solid piece of steel wire.<br /><br />The timer base that Dhadley spoke of is what will be moving under the flywheel when you advance the throttle (you can't miss it). With the engine not running but in forward gear, check to see that it moves smoothly from its idle position up to its full spark advance position (against the rubber bumper) as the throttle is increased to the full throttle position.

 

[trackerdave]

Re: 1979 Evinrude 55hp throttle issue?

Ok, thanks. I'll check the jets and the timer base this evening and report on my progress. Wow, these quick intelligent responses are fantastic. If anyone one has questions about the moving business let me know. I definitely know more about it than repairing my boat motors.