9.5 very sluggish from idle to full speed

[ttgoddard]

Hi,

I have a 1967 Evinrude 9.5hp which is in great shape with very low hours. It used to start up and run like a top, now it will still start on first pull and idle fine. However, when I go to increase the speed, it almost dies. Sometimes I can feather the throttle, increasing it until it is just about to die, then back off, increase the throttle again and gradually I can get it up to full speed, however, sometimes it will not reach full speed, feels like it is bogged down.

I rebuilt the carb, fuel pump, checked carb sync., points gap, replaced plug wires and caps, replaced plugs.

Sometimes it will fire right up, go from idle to full throttle without a hitch, just like the old gal used to. Other times, I get the sluggish hard to increase speed scenario.

I am wondering if the coil or coils could be weak, enough spark at idle, and enough power at higher RPM, but struggles with load under throttle increase.

Any ideas, this one is driving me nuts .

Thanks,

Tony

 

[tashasdaddy]

Re: 9.5 very sluggish from idle to full speed

cover off, watch timing plate is it moving smoothly, or is it hanging up on something.

 

[iwombat]

Re: 9.5 very sluggish from idle to full speed

Have you done a proper spark test?

And now for the standard 9.5 question:

Does it run better with the cover off?

 

[ttgoddard]

Re: 9.5 very sluggish from idle to full speed

Thank you both for your responses.

By timing plate I assume you mean the plate that rotates as you open up the throttle and carries the coils, points etc. Yes that rotates very smoothly with no real play in the linkage etc.

As for the cover off, I tried that and it makes no difference at all, on or off. As for a real spark test, I guess I am not exactly sure what that is, please can you give me some more details.

One thing I should mention. When I replaced the plug leads I noticed one of the coil wires had worn through slightly from lightly rubbing on the cam. One small wire strand was just touching the cam at one point on rotation of the timing plate, I thought ah ha, got it. Put some heat shrink over it, took her out and she ran great, but the next time I took her out, sluggish again. I would say 75% it is sluggish, the other 25% she runs like a top. I thought maybe the heat shrink had some off, but it is fine. I also checked continuity on the kill switch, that is all fine too.

Again thank you again for all of your help, this is very frustrating. I have worked on my own cars, motorcycles and some marine for years and can normally solve most things, but this one has me stumped, but I do think it is spark related not fuel related.

Tony

 

[steelespike]

Re: 9.5 very sluggish from idle to full speed

Sure sounds like a lean condition.I bet if you tickle the choke a little it does better.Many times if you go through the carb again with special attention to all passages and jets (Prove they are clear).Be sure the float is set right.you will get better results.

 

[ttgoddard]

Re: 9.5 very sluggish from idle to full speed

You know now you say that, I do recall doing that and it did take off when I hit the choke quickly, although I haven't tried it in a while. The first time I had the carb off I was almost out of cleaner so I did a real quick job, so later I went back to it and did what I thought was a real good job of cleaning it both with cleaner and then an airline taking out or off anything I could to clean the jets passages etc. I have to say though, it's not the easiest carb to get into the real small passages.

I did also look at the float setting, but will check it again as well as have another go at the carb.

Thanks again for your help.

Tony

 

[iwombat]

Re: 9.5 very sluggish from idle to full speed

It's a good idea to get one of those 1-gal soak cans and soak the carb overnight. Remove all o-rings and gaskets prior to soaking. Sounds like dirty carbs. Good thing the cover off made no difference. The part to replace for that issue is NLA.

 

[ttgoddard]

Re: 9.5 very sluggish from idle to full speed

Thanks to steelespike and Iwombat, you were right it was a lean condition. I guess I didn't see the jet that is inline with the fuel bowl drain plug. When I pulled it after letting the carb soak in a can of Gunk carb cleaner, it was about 75% blocked. I cleaned it out, rebuilt the carb and it now runs great, faster than I think it has run in a long time.

Thanks again for all your help and comments, keep up the great work.

Tony