Help! Pics of Carb. cams for 1991 Evinrude 70 H.P.

joetheis

Petty Officer 1st Class
Joined
Apr 21, 2014
Messages
308
Still tinkering with high idle on my '91 Rude 70 H.P., (actually just looking at it! It's running and I have 2 weeks before it has to travel the 220 miles back to my house).
I took the shop manual upthis weekend, as well as pics of motors I could find. Trying to compare pics to what I have.
All the engine linkages LOOK OK, but I'm still leaning to the 3 carb cam linkages.
Someone had the carbs off, (they are labled), and I THINK they are in the wrong position.
It's idling At 1000 RPM, not a lean idle, The throttle cable is all the adjustment it gone.
Can anyone send me pics of the carb cams as well as the linkage measurement from the cam ramp that lifts the carb to the lever on the engine as well???
Thanks!
Joe
If working on a boat motor was easy, everyone would do it right!
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
I can't help you with pictures but the cable adjustment is NOT part of the linkage adjustment. Throttle linkage adjustments as well as idle speed and mixture are all done with the throttle cable disconnected. When all of the other stuff is done, then the cable adjustment is done. You hold the throttles closed and bring the cable up to its attachment point. Adjust the trunion so the cable can be attached without moving the throttle linkage.
 

joetheis

Petty Officer 1st Class
Joined
Apr 21, 2014
Messages
308
Thanks!
I was pondering through the Evinrude Shop manual I got off E bay last night, lo and behold I found the "lync and sync" section!
It wasn't in the fuel or ignition section, (where it really should be), but the first "general" section??!!
I can see from reading, the cam follower isn't correct, (the marks don't line up), looks like my bottom carb cam isn't aligned either, (my WOT marks are not correct) .
They give a great paragraph on how to find TDC. They use a nice looking tool, but, in the past on bikes I've had good luck with a dial indicator or in a pinch a small wooden dowel.
So, with that info in my head and some great pics, I'm gonna attack it up there.
Joe
Knowledge IS dangerous! I've screwed up a lot of things in the quest to take it from "running good" to "running great"!
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
When you are doing the sync and link, start by making sure that all 3 carb butterflys are completely closed at idle. If one is slightly ajar, That carb will draw extra fuel from the other jet and mess up the idle. The sync and link procedure is part of engine tune-up (a fuel/timing thing) and is why it's not located in the ignition section.
 

joetheis

Petty Officer 1st Class
Joined
Apr 21, 2014
Messages
308
Tanks!
I've done dual carbs (and dual air intake) on my Beemers, but never a triple.
But hey! It's not THAT different!
I think ALL the adjustments threw me, you know if ONE is off, it rocks the whole boat trying to set it up!
I just couldn't find that section in the book for the life of me!!
I kept going back to the fuel section thinking that it was in there and I over looked it!
One other question.............
It states the boat HAS to be in the water to check the timing.
Can I drop the lower unit in a trash can full of water and set/check it?
Tanks!
Joe
This looks like one of those jobs where you read about it and think, "this is a real P.I.A. to do"! Then it's done and you think, "Wow! That was a snap"!
 
Top