1956 7.5 Evinrude. Being very difficult. Questions?

[mettyfish]

I aquired this motor a while back. Decided to refurb it. Put in used but new style coils. Set points. Replaced float with a rubber new one. Carb seemed very clean while apart. Replaced impeller and oring on shift lever. Spark seems great on both cylinders Set low speed knpb to about one turn out and lower knob to 3/4 out. Inspected reeds while carb was off and they seem fine.
Motor runs rough and and seems to be loading up. It vibrates a lot side to side. Although I am running it in a barrel and maybe sucking up some fumes from exhaust but still does not seem to run right.Seems like you can give it almost full throttle and it won't respond quick or won't run at full Rpm. Any ideas what o try next? I have a 5.5 57 model and that one responds perfect so I do have something to compare to. Where exactly shall I start with the high speed and low speed knobs. Thanks for some ideas. Mettyfish

 

[ondarvr]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

At low speed just start turning the needle slowly in either direction, if it runs worse stop and go the other way, do this for both needles (high speed needle at high speed though).

If you do a search you will find a more detailed set of instructions, could be in the top secret sticky at the top of this page, or in the FAQ too.

 

[F_R]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

3/4 turn on the high speed is good for a beginning point, but probably is too rich. Have you tried leaning it out when running?

 

[mettyfish]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

Yea it does seem to idle fairly well but when you go more towards full throttle that's when it seems to load up. It does not die or lean sneeze. Just runs rough. I will try adj the knobs more. Thanks Mettyfish

 

[lindy46]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

How's compression?

 

[mettyfish]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

I have spaced that off but will check compression next. When I changed plugs I look inside cylinders and they looked perfect. But will get readings and let you all know. Thanks, Mettyfish

 

[mettyfish]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

I checked compression and it is 60 on both and I am using the recoil starter. So fine there. I was running it some more and watching spark and it looks to be the same for both cylinders. I can almost open the throttle fully and it runs about a 1/4 speed. But will sometimes pull out of that and rev higher but for the most part 1/4 speed. Carb issue. I did not fully take carb apart but looked to be very clean when I changed float. Still carb issues you think? Thanks, Mettyfish

 

[jimdd810]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

Bingo i would look at doing a full carb job. Should be the ticket and get you on your way.

 

[mettyfish]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

took apart carb again and noticed that the bottom adjustable needle for the high speed knob is not long and sharp at the tip. It is very short and blunt. Pointed but not anything like the top one. It should be the same as the top one. Correct? That is probably why it is loading up bad. To much gas. Thanks, Mettyfish

 

[F_R]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

Nope, that is NOT the problem. The high speed needle is supposed to be blunt. You probably have an ignition problem. Sorry, I don't know what it is. The occasional cutting in of power confirms it. A cylinder is cutting in and out.

 

[ondarvr]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

When it revs or cuts out does it do it instantly like an on off switch, or is a little slower and rougher? Instant is electrical, slower and rough is more likely fuel related.

If you can pull off one plug wire when its running and rev it, you may be able to see if it only effects one cylinder or both.

 

[mettyfish]

Re: 1956 7.5 Evinrude. Being very difficult. Questions?

Thanks, I will try that. It is not instant. It has some delay to the problem. Thanks, Mark