TOPIC: Evinrude '85 50hp tuning question

I have a 59 Glasspar Lido (14') It has a 50hp '85 Evinrude on it (e50ebco), more power than it needs but that is what it has. I am curious if there are any modifications I can make to the motor to have the boat move at a faster speed but not pushing it on to a plane. (i.e. a fast idle? or faster plow?) Right now it goes from a slow speed/idle to pushing it up out of the water to put it on plane. Nothing in between. (FYI: I'm not a motorhead) I picture a solution being where there are different throttle cams that exist? (probably not...) Maybe there are adjustments that are possible? (more likely) I'm pretty unfamiliar with all the different adjustments that are possible under the hood. I've attached a picture of what I have currently.

Any suggestions?
Thanks,
Dave

Your idle stop screw is turned almost all the way in, to the fastest idle position. This messes up the throttle linkage.

Will the engine idle slower? Have you ever tried that?

If you can get the engine to run at an acceptably slow speed in gear, without dying when you shift into gear, then your throttle pickup adjustments will probably work without having to mess with anything.

See how the throttle cam is already touching the carb roller? Where the 2 lines on the throttle cam are, is called the Primary Pickup. It's the point where the carbs are first supposed to open, upon advancing the magneto plate (which is advancing ignition timing).

Normally, you get a fair range of rotation on the mag plate, to advance timing in a smooth and progressive manner, before the throttle Primary Pickup. Then you're opening the carbs, adding even more spark advance, and getting up in the power curve.

Right now, as soon as you advance the throttle, the carbs are opening. This is why you're getting the hair-trigger action.

Note that the Primary Pickup is adjustable; you can move the carb lever that the roller is attached to by loosening the slotted screw that holds the lever in place.

You can also undo the black plastic "yoke" connection to the throttle cam by pulling the cotter pin and taking out the pin that holds it in place. You'll note that once disconnected, the yoke can be turned on the threaded rod for adjustment.

But don't make any of those adjustments yet. You want to get that idle speed setting under control.

And unless your motor is "sick", it should idle down slower. If that part is fixed, then the linkage will be more progressive.

You should be able to back off on that idle stop until the screw has about an equal amount of threads on either side of the Spark Control Lever.

If you're unable to get a lower idle adjustment, there's a way to "Band-Aid" the primary pickup so it comes on later.

But I'm thinking the idle adjustment should work and then you'll get a more normal, progressive throttle action.

After adjusting for proper idle speed, you'll have to re-adjust your throttle cable so it provides proper tension to fully close the throttle (i.e. bring the spark advance lever to rest fully on the throttle stop).

Hope that helps..............ed

p.s. see attached pic for more info.

Thank you for the through reply! I'll start digging into it. I haven't tried anything yet. Figured better asking for help before mucking everything up. Motor has historically 'worked' but am looking to get it working like it should.

When starting it does tend to have very high RPMs (revs quickly and is louder than I would care for / expect.) Does that correlate with what you are seeing with the settings?

Throttle cam and carb roller note makes sense.

>>Right now, as soon as you advance the throttle, the carbs are opening. This is why you're getting the hair-trigger action.
This checks out with what it does.

>>Note that the Primary Pickup is adjustable; you can move the carb lever that the roller is attached to by loosening the slotted screw that holds the lever in place.
I see carb lever is adjustable in two spots (at lower linkage and at upper by carb) Not changing anything now but it sounds like this is a (of a couple) way(s) to get the roller moved farther away from the throttle cam which would delay moving to high boat speed.

>> black plastic "yoke" connection to the throttle cam
makes sense here on how it is adjusted. For reference it seems (without taking it apart) that it is nearly at end of threads.

Motor isn't particularly sick. Been a while since run but no historical issues.

>> You should be able to back off on that idle stop until the screw has about an equal amount of threads on either side of the Spark Control Lever.
Adjustment made. Doing so did pull the cam off the roller just a little bit. Idle stop screw is backed off until just a mm from touching the left copper colored 'stop' plate. So when I push it to the stop plate it wants to rest a mm to the right of it. Before adjustment it was clearly using that plate for where it would naturally sit. Will be a bit before I can test with ear muffs on. (is this a good (but not best) way to test adjustments?)

Next step:
>> re-adjust your throttle cable so it provides proper tension to fully close the throttle.
Is this done with the black adjuster wheels? Looks like one is for choke (outside cable) and the other (inside cable) is throttle (fwd / reverse). This does bring back a memory on the choke. I need to pull it up as far as it can go to easilyish start the motor. But could be tied to the other configurations that need fixing.

Pic attached shows my work. moving the idle stop screw. Thanks again Ed, for the help.

Things I need to research:
throttle linkage
throttle pickup adjustments
magneto plate
fair range of rotation on the mag plate

That looks a lot better, and more normal.

One thing I'd do before getting way far in the weeds, is to make a simple adjustment on that carb lever roller, to delay the carb pickup even further.

You'll note that the slotted arm is at one extreme of its adjustment.

If you loosen that big slotted screw, you'll be able to move the roller farther away from the throttle cam, and this will further delay the opening of the carbs. And should make your linkage even more progressive.

One comment, you've got 2 cables coming from the remote. One is for throttle, the other for shifter. There is no "cable" for the choke, there's probably a manual lever and a rod to actuate the choke linkage, and you probably have an electric choke.

So make the adjustment to the throttle cable and yeah, the knurled "nut" on the cable is the adjustment. Just make sure when the control box is Neutral and the throttle lever all the way back, there is slight pressure pushing the spark lever with the adjusting screw, into the metal throttle stop.

You'll note that when the tension on the throttle cable is adjusted properly, your fast-idle lever will work better. All that fast-idle lever does is allow more throttle in Neutral for starting, without having the shift activated. Be sure that the lever is down for underway operation, after the engine has warmed enough to take it off fast idle.

The electric choke only works when the choke button or switch is depressed/actuated. So on a cold engine, use a little fast idle, and hold the choke shut until the engine fires.

Ed, Thanks again for the help.

Adjustments made. I had a bonus adjustment where I tightened the black Y shaped connection (with cotter pin) to the throttle cam. Let me know if I should undo that one. I adjusted the upper slotted screw that then moved the cam roller further from the throttle cam. I adjusted the one cable and then adjusted it back. I didn't see a whole lot of movement in the adjuster screw. It is touching the (what I assume you call the) (copper colored) metal throttle stop.

For the controls I've attached pictures. As you know, I was wrong in what I was calling the choke. It was indeed the warm up lever.

So lesson time... On the control box I have the gear shifter and throttle (big black arm with red button on under side.) Pull up red button and put into Fwd or Reverse. Push black lever to go faster or slower. (easy one) No tilt/trim on this motor or control box.
On the side of the control box from top to bottom.
Key (easy one) (pretty sure I can push the (already inserted) key in further which may be doing the electronic choke??)
Black dial (no clue, have never touched it.)
Round Black Rubber cap that can be removed (appears to be for keeping it dry) When removed I see a half circle and is rubbery. (no clue, have never touched it.)
Button with red cable (easy one. kill switch for MOB)

Bonus questions... When throttle control arm (black arm) is forward there is a spot where is stops and more pressure is needed to keep it moving forward. (if I recall reverse has same spot) Am I correct that is where fast idle stops and starts becoming something else? (Wide open throttle-ish; faster idle? ) Should the throttle cam and roller start touching at that point? (they don't until WOT is further engaged)

Thanks again for the assistance.
-dave

OK, first thought, only use the fast idle lever to start and warm up in Neutral. Once the engine is running smoothly, push that lever down until it locks.

Then, for Forward or Reverse, you'll pull up on the red interlock in the handle and push all the way forward for full throttle.

The way that linkage is supposed to work, you'll see the mag plate moving CCW first, when you advance the throttle. Eventually, the mag plate comes up to its rubber stop, then that's as far as it will go. This is max timing advance.

After that, pushing forward more on the throttle will cause the spring-loaded spark advance lever to move the carb linkage. So what happens is you get max timing before max throttle. This is an "economy" setting, because you can cruise with max spark advance at a lower throttle setting, and burn less fuel.

When you're really going fast, pushing the throttle all the way, you'll notice the throttle cam is opening up the carbs. So at the most forward travel of your throttle cable, the carb butterflys should be wide open.

That's more or less your "progressive" linkage.

Take 'er out and see how she runs now, I think you'll find that the throttle response is much smoother.

BTW the black knob could be a throttle lever tension adjuster. If you were to screw it in, it should be harder to move the throttle. Screw out, vice-versa.

The rubber cap might be a cover for a tach connection? If that's not it, IDK!

Have Fun on the Water!

I did some digging and confirmed all your thoughts. Nice work!

Warm up lever won't allow you to put the boat in gear as long as it is up. (so works as designed.)

The dial under the key is indeed a friction knob that will prevent throttle creep.

Below the friction knob is a 3 pin connector for a "plug-in" tachometer. One socket is 12v when the key is on, one is a ground, one is the pulse lead (sensor) for the tachometer.

Would testing this on the driveway be of any help (with ear muffs)? I know I can't put it in gear. Just wondering if the changes would be seen in a test like that.

Thanks again!

Driveway testing won't load the engine or tell you much about what it's gonna do in the water.

BTW there's nothing stopping you from putting it into gear when running on a flusher. Just don't rev the engine way up, 'cause that's bad for the innards. Raising speed a bit above idle isn't gonna hurt it any, though.