73 evinrude ignition probs

[glaspar73]

I have had problems with my 73 115 starflite. Engine is hard to start when cold, but if running for a while starts just fine. Also the engine does this thing like it jumps, misses every few moments until warmed up. Then it runs good at speed and at idle. Until recently, after warm up would sputter and run only at half spped. To make things worse I recently left the ignition switch on for a few days and killed my battery. I bought a new one and installed the terminals backward with out realizing it. After that the boat ran about the same. I had read some forums where a guy fixed a problem on the same exact egine by replacing the power pack. when I checked which one I had I noticed that the red wire from the rectifier was close to burning through so I ordered a rectifier and a powerpack .

After installing my new parts and feeling good about myself, I reconnected the pos terminal. WACK a huge spark. Thats when I realized I had the terminals crossed.

Afterwards the motor took a long time to start. but ran and sound good at idle and low rpms. Out in the water slowly increasing power everything felt great and the bam the missing started again and i could only run at 1/4 to 1/2 throttle.

back at the dock with cowl off I noticed one of the coils with a spark jumping across itself every so often.

What now

sorry for this long post

 

[HighTrim]

Re: 73 evinrude ignition probs

Regarding the cold start, what is your starting procedure step by step?

That motor will run a little lean at start until warm, that is the mild backfire that you are hearing.

As you found out, cross polarizing the battery terminals fries rectifier diodes like they are going out of style. You did it twice, but I'll bet you wont do it again now will you? You likely fried the new rectifier you just put in, and it will need to be changed again unfortunately. Lets just hope you did not damage your new expensive pack.

It sounds as if you are not running on all cylinders. I would start with a spark and compression test to see where you stand. Although, visuals such an arcing coil tell you that it needs to be replaced without even testing it. If these coils are all original, they will likely need to be replaced together as a set, along with new plug wires.

Once you have all cylinders firing, you may find that your carb needs to be bathed and rebuilt. But I would do 1 step at a time here.

Let us know what you find.

 

[glaspar73]

Re: 73 evinrude ignition probs

Okay I'm back, Sorry it took so long for the update.

I've replaced all 4 coils. Don't know if reversing the pole fried them but it did fry my new rectifier. So th e engine ran it just would not recharge the battery. So now i've been using it alot and learning everyday.

Still 1 problem still kind of hard to start. I pull the manual choke out all the way and turn over until it tries to start. then I push it in have way and lift the wamer lever under the throttle a little and turn it over some more.
This is when it usually starts. BUT. then at idle it sometimes runs just fine while it warms up but other times it has these semi violent jolts and quits. So I start it again and eventually it goes fine. I have been fishing with it in the morning and for the past few days it will try and stall when I sppeed up after I idle it out if my canal. Once it cranks up the rpms though it just goes great.
I think it must have something to do with the small jets in the carbs, but i'm not sure. Anyway of spraying something in there without taking them apart.

Or maybe some other suggestions.
I got this boat for free and it is so old. it probaly needs everything replaced, but I'm enjoying it so much I like to keep going for a while longer with out spending too much on a boat that could just die of old age tomorrow.

thank you so much for any and all of your help.

Chip