evinrude ski twin timing question

[F_R]

Re: evinrude ski twin timing question

Miss, idle pop, lean sneeze, whatever you want to call it. It is caused by too lean on the fuel/air mixture. Either too much air or too little fuel, results are the same. In your case, it would seem that the carburetor is not running out of gas, expecially if you give the squeeze bulb a mash. So that pretty much says it is not the fuel pump that you are considering.

You have pretty much covered most of the possible causes. But to list some of the most common:

1. SLOW SPEED NEEDLE OUT OF ADJUSTMENT
2. Obstruction in the slow speed circuit of the carburetor. Only way to find it is to take it apart and look.
3. An air leak into the crankcase---can be anywhere. Note: If it is visible, you may see smoke puff out when it sneezes
4. Carburetor throttle butterfly opening too soon (sync). See my previous notes on when it is supposed to start opening.
5. Carburetor throttle butterfly not closing. Something holding it open??? It should be completely closed at slow idle throttle position.
6. Scored piston skirts, or cylinder walls. Broken or stuck rings.
7. Somebody has goofed up something that I have no way of guessing. Crystal ball is broke. Sorry.

Just a thought---concerning #2, you mentioned the needle packings. If somebody had that needle out and pieces of packing got up inside, they may be obstructing the idle discharge ports, found under the welsch plug.

 

[lindy46]

Re: evinrude ski twin timing question

So have you cleaned/rebuilt the carb with a new carb kit, and cleaned the idle circuit under the welch plug?

 

[gwoloshyn]

Re: evinrude ski twin timing question

The carburetor is not the problem. I took the carb off my '69 parts motor (which runs and idles fine) and put it on this motor, and had the same problem. So, it is something other than the carb! I may be pulling apart the powerhead over winter to check out the pistons.

I want to run this motor because it's in really nice cosmetic condition and very clean, where as my parts motor isn't so clean but runs good.

 

[1946Zephyr]

Re: evinrude ski twin timing question

I would recheck your point gaps. A set of points that are too small in the gap, will cause a motor to miss at an idle, but will fire just fine at higher RPMs. I had a car do that once and it drove me nuts till I found it. How do the coils look on this old gem?

 

[gwoloshyn]

Re: evinrude ski twin timing question

The coils look great, I haven't replaced the points/condensors just yet. Maybe I should try that next.

 

[1946Zephyr]

Re: evinrude ski twin timing question

Okay, cool. I would clean and re-gap the points and see if that changes anything. Sometimes, the heels of the points wear down and the point gap gets smaller. Ever set the points on a 6 cylinder Merc 800?? Oh boy, these are fun to get set right.

 

[F_R]

Re: evinrude ski twin timing question

I would recheck your point gaps. A set of points that are too small in the gap, will cause a motor to miss at an idle, but will fire just fine at higher RPMs. I had a car do that once and it drove me nuts till I found it. How do the coils look on this old gem?

Good point. I would think that stuff like this would have already been checked, but who knows?? If the points are grossly mis-adjusted , it is the same as advancing or retarding the spark, which is the same as improper timing in relation to carburetor sync. Same goes for excessive armature plate wobble, etc. Hard to tell without being there to looksee.

 

[gwoloshyn]

Re: evinrude ski twin timing question

I pulled the flywheel and checked the points. One side measured .013 and the other .015. They also look pretty worn as seen in the picture, am I right? I'm going to order a tune up kit and maybe, hopefully that will fix my problem. Thanks

 

[F_R]

Re: evinrude ski twin timing question

Go ahead and try it, you have looked at everything else. But I have my doubts. Sorry.

At .013" they were too close, resulting in retarded spark.

 

[1946Zephyr]

Re: evinrude ski twin timing question

You actually can clean those points up and re-use them, but if you would rather replace, thats not a bad idea either. One thing nice about these ignition systems, they're pretty forgiving and you can clean and file those points for years. Those coils look great and will do ya for many years to come.

 

[lindy46]

Re: evinrude ski twin timing question

As long as you've got her opened up and torn down that far, I'd drop in a new set of points and condensers - only about $20. Then you won't have to worry about that for years.

 

[1946Zephyr]

Re: evinrude ski twin timing question

Yea, if it's a motor that you plan on keeping and using, that would be the best idea. However, I can pull the flywheel and replace the points and condensors, inside of an hour, on a Skitwin. These things are easy to tune.

 

[gwoloshyn]

Re: evinrude ski twin timing question

New points and condensors installed but still have the same problem. Now, it will barely start and stay running.

 

[1946Zephyr]

Re: evinrude ski twin timing question

Very odd. With a new ignition system, that thing should be runnin like a champ. There must be something that is out of whack. When you turn your crank to where the "Top" indicator lines up with the heels of the points, is where you gap your point's (.020). The inspection hole on the flywheel should get you in the right vicinity too. The low speed needle should be set on 1 1/2 turns out and the high speed at 3/4 turn out. If you have these areas set as listed, then you should be able to run okay. The spark plug lead connections at the coil and the spark plugs are also important too.

 

[gwoloshyn]

Re: evinrude ski twin timing question

Where is the "top indicator line" for setting points? I was under the impression that the whole lobed area on the crankshaft is where I can set my point.

 

[HighTrim]

Re: evinrude ski twin timing question

It will actually say the word "TOP".....if that is not there, the flywheel key.

Set it so that a 020 feeler gauge will just pass through, a 022 will not and a 018 will with ease.

Be careful not to get them dirty, even a fingerprint will cause issues. Clean with acetone when done.

 

[1946Zephyr]

Re: evinrude ski twin timing question

You'll be able to see it. You'll see "TOP" with an arrow next to it. They may have done away with that, by the time the 33 was built, but as I understand it, the 33 was built with leftover parts from the 1957-58 Big Twin and should still be there. If it's not, just look for the high point of the lobe and set your points by it. Slowly turn the crank a little at a time and check the gap at each location and you'll see where the highest point is. These ignition systems are pretty forgiving.

 

[gwoloshyn]

Re: evinrude ski twin timing question

Thanks for the info.

I'm thinking it may afterall be fuel pump related, it seems the motor won't start because there's no fuel going to the carb. I'm going to have to order a new pump I guess and go from there.

 

[1946Zephyr]

Re: evinrude ski twin timing question

Well, before you condemn the fuel pump, it's best to check it first. Check and make sure the fuel flow is free and what you can do, is once you charge up the fuel system, remove the fuel line from the carb and stick it in a jar. Fire the motor up and see if the fuel pumps pumps gas into the jar. Also make sure your fuel tank is vented properly too.

 

[gwoloshyn]

Re: evinrude ski twin timing question

Well ever since I got it back together gas leaks out the side of it when I prime the bulb, so I'm thinking the gasket needs replacing.