Weird issue with adjusting idle stop screw, idle timing, etc...

[rusirius]

And btw, it was running fine when I shut the key off yesterday too to verify it was good. Anyone looking to buy a boat? Lol

 

[rusirius]

So yesterday I built a DVA adapter for my meter. There really isn't anything to these... It's just a half wave rectifier with a cap to store the charge so the meter can read it. I even popped a push button in there to drain the cap to "clear/reset" it.

Anyway... I checked out the charge coil and I was getting about 260v from it during cranking... Service manual says anything over 250v is good.

I checked all 3 coils on the timing base and get absolutely NOTHING... Zero... Zip... Zilch... Nada....

Now ordinarily I'd question my EE skills and think my adapter sucked except A) I got no fire to any cylinder and B) it seemed to work perfectly for the charge coil...

What I just can't understand is how I can put everything together, it starts up and runs just fine... Shut it off via the key, don't touch anything, come out the next day and all 3 coils in my timing base have went bad?

That just doesn't make any sense to me at all.

Regardless I've ordered a new one anyway. We'll see what happens...

 

[oldboat1]

bad keyswitch? believe black and blk/yellow stripe usually the kill circuit.

 

[seabird89]

This is probably wrong because you sound like you know more about this than me, but did you try with the black wire with the yellow stripe disconnected?

 

[jakedaawg]

If he is testing sensor coils the blk/yel doesnt have anything to do with it. Set dva to neg and 5 volts. Your homemade one may not be the right tool for this case. You soundnlike you are useing a modified multi meter. Turn autorange off maybe. You EE guys are way smarter at this than I though.

As for the no spark they are correct in that the first step is to double check the kill switch, second is to open the blk/yel at connector by the pack.

 

[rusirius]

Yeah I tested the e-stop (blk/yel) at the pack before throwing a dva together.

Out of curiosity, just to verify what I think I know. Aside from the e-stop, the most likely cause of no fire in all 3 cylinders is the power pack right?

Aside from that, a failure of all 3 trigger coils, or charging coil, or all 3 ignition coils are the only things that could cause that correct?

 

[seabird89]

Which wires are you testing on the timer base? Does it pass the ohms test? What is your meter set to?

 

[jakedaawg]

Key switch, emergency switch, blk/yel short to gnd, power pack, all more likely than timer base or 3 coils all at once.

 

[rusirius]

Which wires are you testing on the timer base? Does it pass the ohms test? What is your meter set to?

There is no ohms test on these coils. For some reason they're a bit different than most. They have a ridiculously high resistance, ad's when you measure resistance that high there are way too many factors (I.e. Contact impedance, probe length, probe design, etc) that play into the measurement to give any sort of usable range to test for, instead they (cdi) just tell you too check to make sure they all measure close to the same, which in my case they did, all about 10 megaohms. (That's 10 million ohms, compared to most coils that measure around 30 ohms).

I replaced the timer base and now have spark. But it's still acting weird and irregular, so I still think the power pack has issues too. I'm getting the new power pack in today so I'm hoping that will address that.

 

[rusirius]

Yet another update...

So I replaced the power pack after work tonight. Fired it up and it started and was running much better, but still not right.

I'm not sure if I'm screwing something up with adjusting it or what.

The service manual calls for idle timing if -4 degrees, but I can't seem to get it below about +4 or it dies. I also can't get the throttle arm all the way against the idle stop. I did a link and sync and that looks good. When it is against the idle stop the cam just barely sits off the cam roller, pushing the throttle forward the mark on the cam line up perfectly with the roller just as the butterfly shafts start to turn. As far as I can tell this is exactly what should be.

But it won't even come close to running like this. I have to advance the idle (and therefore open the butterflies just a bit) to get it to run. I assume maybe that's normal.. But

When trying to adjust the idle mixture screws the middle cylinder is the only one that really seems to be acting the way I would expect.

I start with the middle carb, turn the needle in 1/8th and give it a few seconds to catch up. The rpm picks up and I do it again. Rpm picks up, do it again, etc. The service manual says to start at 2 to 2 3/4 out. When the middle carb starts coughing our engine dies I back it out about 1/4, which leaves it about 3/4 of a turn out.

I then move to the top cylinder. It reacts completely differently. I start turning it in but rpm doesn't really change much. Sometimes I think it might go up just slightly, but it seems to bounce back down after. Then once I get so far in each 1/8th turn drops the rpm, though the idle seems to get more stable, less shaking, etc. Yet it continues to go down reach turn until it dies. When it did I turned it back a little over 1/4.

Then the bottom cylinder yet again acts completely differently. As I turn it in nothing really happens to the rpm at all. Eventually the next turn the engine dies. So I turn it back out 1/4.

Then I try to move the throttle arm closer to the idle stop to slow it down (usually by this point it's running about 1700rpm. I get it down to maybe 1500 and it suddenly drops too about 800 for just a second and then dies. I can repeat it over and over.

So I thought maybe instead of adjusting the throttle I need to adjust timing to get it closer to spec, but it kinda acts the same way, I back it down just a little and all of a sudden it'll just drop way down and die a second later

I'm pretty much at my wits end with this thing. Does anyone have any suggestions here? Is there something obvious I'm doing wrong?

 

[oldboat1]

Are you still running on muffs? If so, get a large container -- big plastic trash can will work. You need to see what the idle speed is with a little back pressure. Just keep it in neutral, and get the water about half way up the leg -- keep the hose running, and let it idle. (You also need to be able to hear the engine above the exhaust noise, which is tough on muffs.) This is not as good as running in the lake, but should be an improvement for testing.

I don't recall what you did in the way of carb work and fuel work -- think you decided the VRO was now working OK. I would be inclined to test run with a portable tank and fresh 50:1 premix, blocking off the VRO oil feed -- but your call.

You may have reed valve issues, so if ready to pull off the carbs for cleaning and rebuilding, consider checking reed valves. In your initial post you referred to sneezing back through the carbs, and it seems clear you can't get the carbs adjusted -- both potential signs of broken reeds. Additionally, I don't recall whether you checked for intake leaks which can also make tuning impossible.

Correct me if this covers old ground.

 

[juno pierrat]

on my older 48 spl 2 cylinder I got it to idle better by gradually adjusting the cam roller tighter to the cam, touching the cam, then adding a 1/2 a turn to the thumb wheel adjuster over several trips until it idled great,only about a turn or turn and a half, and yes to running in water or barrel, mine on muffs idles about 1200 to 1300, hope this helps, don't let this story get you off track the other guys helping have much more experience

 

[rusirius]

I put it in a can this morning to get it off the muffs. Tried to adjust the idle mixture again and basically had the same response. The middle one acts just like I'd expect it, top and bottom not at all.

I'm kicking myself for not checking this earlier, but here's what I found.

While running if I pull the top plug the motor slows a bit, but usually still runs.

Pull the middle plug and it dies immediately.

Pull the bottom plug and it does nothing. No rpm drop, no sound change, nothing.

And btw, I'm basing rpm off a tach clipped on a plug wire, not just by ear.

So obviously the bottom cylinder is doing nothing and the top one isn't doing much. At this point it looks like it's mostly running off the single middle cylinder.

Of course the first thing I did was pull plugs and check spark, but I've got great fire on all 3 plugs.

The fuel pump is pumping fuel great, carb bowls are full of fuel.

I didn't pull the intake, but I did pull the carbs and look at the reed valves, they look good from the back side.

I'm just not sure where to go from here. Obviously for some reason those two cylinders aren't doing much, the bottom nothing at all. I didn't rebuild carbs, but I did pull them down, clean them up and make sure floats were set correctly. Is it safe to assume at this point it's a carb issue? Or is there something else I should check?

 

[oldboat1]

Spark is tested with an adjustable open-air tester (look for 7/16" or more). Run it in the evening to look for arcing along the wires. I would recheck compression as there were some earlier questions, and retorque head bolts as you had the head off. Reseating the head cover usually requires resurfacing (expect warpage), and a fresh gasket, then retorque after running.

Carb cleaning requires full disassembly, and soaking of all metal parts -- then cleaning out all fuel and air passages with compressed air, carb cleaner, some gentle poking with soft wire or similar. I normally leave jets in place for soaking, as they can be damaged. Your call as to how thorough the cleaning was.

You can spray some carb cleaner around the intake manifold and down around the bottom of the powerhead (lower shaft seal) and see if rpms change -- checking for leaks. Shield the carb intake for testing.

Did idle rpms drop when off the muffs?

 

[rusirius]

Ok, retorqued head bolts. Didn't really change, still at 20. Rigged up a poor man's spark test and it jumped 7/16th on all cylinders with no problem. By your standards I would say carb cleaning was thorough, I did the things you specified.

Idle didn't change much if any in can versus muffs. Not noticeably anyway.

I did some additional testing and I'm even more confused.

I swapped #2 carb with #3 carb. #2 was the one responding right and seemed to be the only piston really carrying the engine. #3 seemed for all intensive purposes dead. Pulling plug made no change to rpm.

After I swapped carbs the problem stayed exactly the same. The old #3 carb that is now on #2 is working great. Needle adjustment works just as expected. The problem stayed with the cylinder(s) and not with the carb. So it looks like carbs are fine.

Lastly here's another strange thing, or I thought it was though maybe there is an explanation.

I pull the plug for#3 and idle didn't change. Keeps running exactly the same.

Yet if I pop my hand over the throat of any carb, including #3 the engine stumbles and if I don't remove it immediately it dies. #2 seems a little more sensitive (I.e. I have to remove my hand quicker or it dies), but I can't stay on any of themlonger than a second or it dies.

That doesn't make a lot of sense to me. If it doesn't change without spark the cylinder should basically be dead, So why should it care if it's getting air?

 

[oldboat1]

Spray a little carb cleaner or WD-40 around the base of the powerhead while running. See if there is any change in rpms.

 

[rusirius]

Spray a little carb cleaner or WD-40 around the base of the powerhead while running. See if there is any change in rpms.

No noticeable difference in rpm with carb cleaner except when a bit of overspray got sucked into the throats of the carbs, then the rpm dropped a bit (couple hundred rpm) for a few seconds then cleared.

One thing to note that seemed odd but maybe normal I dunno. With it set where it is now the idle is about 1400rpm. The timing is about +5 degrees.

A couple of times the engine would stumble and the rpm would drop to about 750rpm. Sometimes it would run a few seconds like that idling somewhat normal, though just slightly rough, then it would jump back up to 1400 again.

What's odd is I noticed when this was happening the timing would drop to about -4, where it's supposed to be according to the specs.

At first I thought of the quickstart, but the thermo switch checks good, nothing when cold and grounded when warmed up a little. And it's a brand new power pack.

But it sure seemed like the quickstart was kicking in and out because the timing base wasn't moving, but the timing certainly did when it did this.

 

[seabird89]

Did you test the new timer base for correct output? Also, did the flywheel magnets look ok, including the center hub magnet for the timer base?

 

[rusirius]

Yes timer base output looks good, as did flywheel magnets and hub.

 

[rusirius]

Ok, so today I happened to come across an '85 evinrude 70hp that runs good for a ridiculously good price. So I bought it. So now I'm hoping you guys can help me with a couple of new questions...

The motor I bought looks almost identical to my 93 60hp. But it doesn't have power trim and tilt.

So I have two possible options I can think of. Either I swap the power head off and just pop it on my existing lower and housing, or I swap the trim/tilt base.

My question is, which of these is easier and/or possible? I'm not sure the process involved in swapping the trim/tilt base. It looks like the shift rod runs through it, so???

As for swapping the power head, like I said it looks almost identical to mine except a few minor details (like no quick start, smaller rectifier, etc)

I'm sure the bolt holes will match up, what about the splines or whatever?