sync and link

[mkpj1]

I tried to search for this info but wasn't able to find anything. I recently purchased a 67 Evinrude 40HP (Lark). I have replaced everthing and it fired up nicely. Took it to the lake and it felt doggish and a little rich. Reset low idle with no real change and advanced the throttle some with no real change. I have built several car engines so I thought about timing and found the chapter in Seloc on Synchro. It was so far off the mark that I am second guessing the change? I fired it up and at first it idled high, 2500 grand maybe ( do I need a special tach, Mine's for auto's, can I double 4 cylinder?). Seemed strong and I readjusted the throttle to bring the RPM's down to a comfortable level. The throttle is very responsive now of course i am in a tank so I won't know the difference until I put it on the water. My fear is that it is so repsonsive and running much cleaner (no gross tank water, Lean) that I could blow the motor. I mean I have a lot of room to send RPM's to the roof in the tank.

This is my first boat motor and it's old so I rather ask a really dumb question than go out and ruin the motor.

Also, The motor has a screw that limits the armature with a plastic piece. Is this a rev limiter and if so how is it set?

Thanks,
Ken

 

[JB]

Re: sync and link

You need a Service Manual, Ken.

NEVER rev an outboard with no load over about 1500rpm.

 

[tashasdaddy]

Re: sync and link

e mail me i'll send you the link for setting the carb correctly so you are not to lean. tell me you need Joe's Carb setting your is not old i have a'55 15hp i use all the time.

tashasdaddy@comcast.net.

 

[mkpj1]

Re: sync and link

JB,tashasdaddy,

Thanks for the quick response. I have the manual and a seloc plus the parts manual. I followed it to the "T" but the problem is that thes manuals are written for the experienced boat mechanic so I just want to be sure I'm not missing something when I sync the motor. Once I adjusted the throttle to bring the RPM's down it ran fine and much cleaner than before with less smoking and unburnt fuel. I think I'm okay. I just wanted to be sure I wasn't missing something because th manuals are so vague. .

There is nothing in either manual that covers this, what I think is a rev limiter of some sort. The parts manual has a idle stop screw that may be it but the diagram is not real clear. If it is an idle stop, how is it adjusted because there is nothing in either manual. My Larson has controls that have an idle adjustment but there is no cable and I am wondering if the cable at one point would have connected into this system somewhere? Any ideas?

 

[Silvertip]

Re: sync and link

The idle stop screw is just that. It stops the throttle linkage from moving any lower. The idle speed control on the controller is a vernier adjustment that provides slightly more idle by moving the throttle cable that the control lever moves. There is no rev limiter on that engine. There are ignition advance limit adjustments. One for idle and one for wide open throttle. Those settings are the ones you need to get right. Too much advance and you cook the motor. Link & sync and your carb mixture and speed adjustments are separate issues. Link & Sync synchronizes the movement of the advance mechanism with throttle opening. Get that right then go after idle speed and idle mixture adjustments. Otherwise you end up getting nowhere. You really need a manual specific to that engine. Check your library. Link & synch is far too detailed to go into here.

 

[KYHunter2]

Re: sync and link



Yes you should be able to double the rpm's for a 4 cylinder .

I know before I bought my new guage .

The old one required doubling the rpm's for an 8 cyl., to get 4 cyl. rpm's.

You also can't deviate, from the procedure, during the link. and sync.

You must go step by step , in order.

If you change anything afterwards.

You'll end up starting over , most of the time.



KYHunter

 

[KYHunter2]

Re: sync and link

Sorry, I messed up and kind of dble. posted.

KYHunter

 

[tashasdaddy]

Re: sync and link

they hit it on the nose.

 

[mkpj1]

Re: sync and link

Thanks for the reply's

Silver, that helps a lot but I still dont know what the heck that screw is that limits the throttle cam from turning clockwise (or advancing). The screw is large and is in the eleven o'clock position in relation to the low speed idle knob. It adjusts against a plastic stop that limits the throttle cam. There is a stop on the throttle cam that projects upwards just prior to the marks for synchronization that butts up against this plastic piece. I have the Evinrude service manual for the 1967 Lark and it does not address this screw at all. Nor does the Seloc. I guess if an over advance would cook the motor then you could have this a safety stop of some sort. I don't understand this system enough yet to know.

KYHunter,

Where is the easiest place to put the green tach wire? Ignition on the solenoid?

Thanks,
Ken

 

[jtexas]

Re: sync and link

wait a sec...4 cylinder 4-stroke...fires 2x per rotation...2 cylinder 2-stroke fires...2x per rotation...what am I missing?

 

[Silvertip]

Re: sync and link

Some pictures of what you have would sure help. If you find a picture on-line somewhere give us the link. Not all of us have the manuals for every outboard built and since I'm a duffer and may have worked on that engine when it was pup, that was then and this is now. To put new stuff in the old brain I had to push some old stuff out so I don't recall the exact configuration either.