1976 Evinrude 15 Questions

[chevysam41]

Hello All,

I have a 1976 Evinrude 15hp outboard (15604A) that my grandfather bought brand new. The outboard was used and taken well care of until he passed away in 1988. After that time the outboard was dismounted from the boat and stored indoors in a dry environment. I'm trying to restore the motor to operational status. I've done many hours of research (thanks leeroy!) and have replaced the following:

* Water pump (complete)
* Lower unit oil (Hi-VIS)
* NGK B6HS spark plugs gapped to .030
* Coils
* Carb rebuilt (the slow speed needle is bent ever so slightly)
* New thermostat
* New fuel pump (and lines)
* Greased the prop shaft with triple guard

I was able to start the motor up a couple of days this week. All together, it has run for less than five minutes.
1) When the motor is idling in neutral, it produces a moderate amount of white smoke. Is this normal for a motor that has been sitting for almost 30 years?
2) The motor doesn't seem to want to idle at a normal RPM (by normal, I mean what I tend to see online for these motors). Could this be a result of incorrect A/F ratio?
3) May be a dumb question, but is the 1 1/2 turns from soft seat...seating the idle needle by hand or with the knob attached? (soft seat with the knob on is much further in the carb.)
4) I let the motor idle for about 2 minutes or so on 1/26. When I looked at it yesterday, there was a grey watery/slimey mixture in the propeller hub (see attached photo, but it isn't as thick as it looks). Is this normal?

I'm very mechanically capable and know my way around GM LSX engines, but I'm new to outboards and hoping you all can shed some light. I have a couple of videos of it running that I can post if that would help.

Thanks!

 

[poida]

Do a compression check on both cylinders.

 

[chevysam41]

Thanks for the reply, poida. I did have compression checks on my agenda. My understanding is that this needs to be done on a warm motor, correct?

 

[OptsyEagle]

I am going to need a little more clarification about the issue of the difference in soft seat with the knob on or off.

Basically with the knob on, you dial in the slow speed needle until it lightly seats. You will need to pop the knob off and back on again a couple times since it will not do a full revolution with the knob on. When it is lightly seated, turn it out (counter-clockwise) 1.5 turns. Start up the motor and let it warm up. Now bring the motor to as slow of idle as you can. Dial in the needle 1/8 of a turn and let the motor respond for 10 seconds. If the idle increases slow it down again. Keep doing this until the motor hiccups, sneezes and wants to stall or does stall. Turn the needle counter-clockwise 1/4 turn and leave it there. Adjust the knob to point halfway between rich and lean and you are done.

Try that first. Your idle problem may come from the bent needle you mentioned. I can't say because I don't know how much it is bent, but is should be perfectly tapered to work as designed.

You also want to ensure your link and sync is set properly. When the throttle roller just touches the throttle cam the arrow on the throttle cam should be in the middle of the carb's roller. This synchronizes the carburetor to the spark timing of the motor. At the lower idle levels the carb butterfly will be completely closed and it is only the spark advance timing that changes the idle RPMs at the lower idle levels. So you should ensure that is set properly if you want to get a good idle and top performance at all the other throttle ranges. To adjust it, if it needs to be, there are two hex nuts under the flywheel on the starboard side of the motor.

The sludge on the propeller is normal. It is just unburnt exhaust gas and oil. It is usually more prevalent when you are idling a 2 stoke motor in a barrel of water. 2 stokes prefer to be run hard with a load to get the best combustion of the fuel. The water in the barrel usually becomes pretty sludgy as well. This is normal.

 

[gm280]

:welcome: aboard chevyam41 to iboats...

You can do a compression test while cold. What you are looking for is both cylinders being within 10% readings of each other. So post those results.

 

[chevysam41]

Eagle,
Your description of how to adjust the slow speed needle tells me I was doing it correctly. I could see how someone would set the needle with the knob detached and without having the knob on, lightly seated wouldn't be screwed in as far. Therefor, the needle would be out far too much. Hopefully that makes sense. The slow speed needle isn't bent much. Its hard to tell it is bent even in a photograph. The needle was bent when I took it out the first time, so it has been like that for a long time. If all else fails, I may replace it to be on the safe side (they want an arm and a leg for one of those). Interestingly enough, when I rebuilt the carb., it did not appear to have the small white bearing that comes in the rebuild kit. I put one back in though.

Good to know the sludge is normal. Based on your information, it makes sense because I haven't even run the motor in gear yet. Only neutral. I'll double check the link and sync. Based on the wealth of pictures I took before I disassembled anything, I think it is all back together correctly.

I also have new points and condensers for the motor. I haven't installed them yet, just had them on hand in case. Should I consider replacing these anyways once I sort the other issues out? I know with the old wheel horse tractor I had it wouldn't start if the motor was warm (product of the P/C going out).

GM280,
I'll try to do a compression test sometime this weekend or early next week. I hear 80-100 is fine, does that sound right?

 

[gm280]

Interested in the bent needle. Can you post a picture and tell us what part is bent. If the threaded section is bent, not too much to worry about. But if the very end of the needle (the point) section is bent, then it can make things harder to adjust. Post a picture with a straight edge aside of it for comparison.

Some times, with great care, you can straighten them back. But you have to use some finesse to do it correctly. And to see how well you are straightening it, roll it on a flat table or surface and watch the pointed end for run out or wobble. When you get that steady, it is straight. JMHO!

 

[chevysam41]

I didn't know you could re bend those needles. I'll snap a pic this weekend, but I'm pretty sure the bend is about halfway up the threads so it may not be an issue.

 

[flyingscott]

Make sure there was not another bearing in the carb they tend to stick in there you could have 2 in there. Also what rpm is it idling are you adjusting it on muffs or in the water the idle is adjustable on the side of the motor. Also if you have aftermarket points and condensers take them back and use only factory points on that motor. They have an ignition that is hard on points and the factory ones last a lot longer. Another problem with that motor was kind of a bad idle they made a smooth idle kit for that motor that had a new head and carb.

 

[gm280]

I didn't know you could re bend those needles. I'll snap a pic this weekend, but I'm pretty sure the bend is about halfway up the threads so it may not be an issue.

Most of those needles can be worked if you go really careful. I've bent them back, but very carefully. I look at it this way, if it is already bent and you are contemplating replacing it anyway, why not try to straighten it first and see if you can save the purchase? Sound like a plan to me. :smile:

Post the pictures.

 

[oldboat1]

Hi Chevy. I usually set that l.s. needle when finished rebuilding (1 1/2 turns out, like you said). When the carb and air horn installed, push the knob over the stem with the stop set so you can rotate a half turn either way. Adjust it in the water and at temp (muffs won't work well, as you need back pressure). Set the throttle as low as it will run smoothly, then lean out the mix 1/8 turn at a time. When you get a lean sneeze, back it out richer.

If you run in a barrel, sink it about half way up the leg. Think the stuff at the prop will clean up with running -- probably more to work through from the exhaust housing after storage. Can check temp with the old hand-on-head method. If too hot to touch, it's too hot (usually can hold the heel of your hand on the top of the head for a few seconds -- tells you it's around 130-140F). Temp gun is better and more fun (measure at top of head). When you have it running smoothly, I would just let it idle for a while, checking temp now and then.

 

[Chinewalker]

Some goo in the prop outlet area is normal, particularly when running in a barrel. 2-strokes are messy beasts. Excessive amounts of white oily goo can point to a misfire (some fuel running through unburned) or running rich due to carb issues (too much fuel running through). Also, it's a 2-stroke - it's gonna smoke.

 

[OptsyEagle]

Interestingly enough, when I rebuilt the carb., it did not appear to have the small white bearing that comes in the rebuild kit. I put one back in though.

I also have new points and condensers for the motor. I haven't installed them yet, just had them on hand in case. Should I consider replacing these anyways once I sort the other issues out? I know with the old wheel horse tractor I had it wouldn't start if the motor was warm (product of the P/C going out).

GM280,
I'll try to do a compression test sometime this weekend or early next week. I hear 80-100 is fine, does that sound right?

Those small white bearings are very hard to see when they are used and installed inside the slow speed orifice. My guess is that you probably now have two in there, but it is just a guess. The best way to get them out is to straighten out a fish hook with a barb on it. Insert the hook into the orifice and hopefully the barb will bite on the bearing and come out. I would want to give that some thought and attention. The bearings are cheap so if you are ordering new parts, get another one and pull out whatever is in there and if I am wrong and you do only have one in there then you are out maybe a couple bucks, but at least you know for sure.
Just be careful with the fish hook or whatever you are using. That carb is made of aluminum and everything else seems to be steal and you don't want to ruin that jet orifice or the carb will be toast.

As for the points. I am surprised that a motor that has sat since 1988 gave you any spark at all. Those points are notorious for corroding after even a couple of years of non-use and killing the ignition spark. Once you told me you had it started, I figured you were good to go. So obviously the current points and condensers are OK. What might not be OK is the current point gaps. Over time the point gaps, that should be set at 0.020", will narrow from the erosion of the rubber material that contacts the points cam. This will narrow you point gap. As that happens your spark timing starts to happen a little more after top dead center. This will reduce the motors top end performance and its ability to idle properly. It is why a tune up (re-gapping and cleaning the points) should be done every 3 years or so. If you can remove the flywheel I would recommend doing so. If you are going to do that, and you own new points and condensers, you might as well install them. Gap the points at 0.020" and get that motor tuned to perfection.

Any compression that is over 80 psi and with both cylinders within 10% of each other is fine. My 15Hp 1976 motor puts out about 105psi on both cylinders. I think that was cold tested. Don't worry too much about the exact value or whether it is hot or cold. The most important thing is that the compression of both cylinders are close to the same.

 

[chevysam41]

Make sure there was not another bearing in the carb they tend to stick in there you could have 2 in there. Also what rpm is it idling are you adjusting it on muffs or in the water the idle is adjustable on the side of the motor. Also if you have aftermarket points and condensers take them back and use only factory points on that motor. They have an ignition that is hard on points and the factory ones last a lot longer. Another problem with that motor was kind of a bad idle they made a smooth idle kit for that motor that had a new head and carb.

Funny you should mention that. That already caused me an issue. I installed the new bearing and afterward, after thinking I might have two installed, I removed the one I'd stuck in there, but destroyed it in the process. Afterwards I confirmed there was not already one installed. Ordered a whole new rebuild kit ($20) - you can buy just the bearing, but that small piece of plastic is $10, so why not get the whole kit again.

Thanks for the heads up about the P/C. They're sierra brand, so I'll avoid using them. If I do need to replace the OEM ones down the road, sounds like I should stick with Johnson/Evinrude brand. Interesting about idle kit. I think I read where in '77 they converted to a head cover/thermostat housing that is scalloped near the spark plugs and is 8 bolt as opposed to 7 bolt. The one I have is an 8 bolt (and def. a 1976 model) - I wonder if it is a late '76 model or if it was converted to the smooth idle kit.

So far I've been adjusting everything on muffs, but sounds like I need to put it in a barrel. As for the idle, I'm not sure since there is no tachometer. I'll see if I can post a video. I saw the idle adjustment on the side. Can anyone explain how that works? All it looks like to me is a paddle that touches a lever, but that lever is attached to a screw, so I don't see how that does anything at all. Maybe it wasn't installed correctly before it was put up for storage?

 

[oldboat1]

There was the scalloped t.stat cover, and then later the scalloped cover with two lower bolts. The two lower bolts was a large improvement, IMO (saved some potential gasket leaking). But I think that came around '85. Be aware that the cover is difficult to get off because of it's location up against the cover latch down at the bottom. Leeroys site refers to that problem, and I've tried his solution just for grins (altering latch assembly) -- works, but probably isn't worth going to the trouble (MO). I take off the cylinder head and change out the t.stat that way (need two gaskets). With the head off and on the bench, the t.stat gasket and cover can go on with no difficulty regardless of the bolt arrangement. I prep the t.stat cover the same way as the head gasket (flat surface with fine grit sandpaper). On the t.stat, think I would suggest not messing with it unless it clearly needs to be replaced. (If grandpa ran it in saltwater, think I might go ahead and replace it as routine maintenance. Otherwise, I would run the motor and see if temps are what they should be -- surface temp around 140 at the top of the head, no hotter than 160.)

The idle adjustment wheel moves the paddle laterally, as you describe. They are a replacement for the older set screws which did the same job (which I prefer, but that's just me). There is all kinds of discussion about 9.9 and 15 hp carbs, usually moving up to the 15. I have a couple of 9.9 Yachtwins with 15hp carb bodies but presumably with the middle sized jets (sized between the 9.9 and the 15). I'm happy with operation, both at idle and at speeds.

[ed. second read -- see you handled the t.stat already....good to go.]

 

[chevysam41]

Update:

Oldboat1: I now see how the idle adjustment on the side works - I think that knob being called an "idle adjustment" is somewhat misleading.

I did a compression test on the motor last night. I did four tests on each cylinder, and all tests on each cylinder were 70-72psi. That sounds a little on the low side based on what I've read, but everyone seems to put more stock in both cylinders having similar readings. I also took a couple of photos of the slow speed needle (see attachments). You can see that the needle isn't bent much, and it looks like it is further up the threads, so hopefully it isn't an issue.

I also noticed an issue with the tiller and the throttle (that I should've caught before now). In short, the red indicator on the tiller handle doesn't seem to line up correctly. It will turn smoothly in the slow/fast directions, but the red indicator won't go past about halfway between "start" and "fast" (see attachment)...because the throttle cam is hitting the stop lever (WOT). However, the red dial will go well past "slow" (see attachment). As a result, if I turn the dial as far in the "fast" direction as possible, then go back in the slow direction, the throttle is still at WOT until I get about halfway between shift and slow. This can't be right because under this condition you would be starting the engine at WOT.

I took the tiller handle off maybe a week ago to clean it and re-grease the teeth (the whole assembly was a bear to operate in its previous condition). I guess it is possible that I didn't something back together correctly. I don't know how that could have happened though since the teeth and tiller assembly will really only go back together one way...

 

[gm280]

Sam, seems the needle is bent, but it looks to be bent towards the outer portion. I would try it like it is first to see if it will adjust out okay. Is it made out of steel or brass? Secondly, sometimes those tiller handles have to mesh with gear teeth and can easily be installed one tooth off. So maybe look for that. The compression looks a little low, but before I would break into the engine, I would run it first and see how it works out. It could be that there is some carbon build up and once it is run it could gain some additional compression. Could even run it and use some Sea Foam through it and see how that cleans it up. JMHO!

 

[AlTn]

put the motor in forward gear...can you now get to wot with the carb roller on the highest point on the cam... the throttle plate is fully horizontal in the carb throat.. and the timing is fully advanced?..if so, you're good to go...the slow, start, fast markings are viewed more as "guides" than absolutes...for starting, try advancing the throttle as far as it will go with the motor in neutral, full choke and it should at least " cough" within 4 pulls...if it does cough, go to half choke and it should start and run...you can kick the choke off and reduce the throttle setting so it doesn't "jerk" when you go into gear....warm engine shouldn't require any choke or any throttle advancement in neutral to start

 

[oldboat1]

^^^agree. May have to set the l.s. needle slightly richer for cold starting, then lean it back out when warmed up (do that on one of mine). That idle adj knob is probably more of a limiter -- adjusted to keep the idle high enough to remain running. Actually, if everything is top notch, you can get a very slow idle with the twist grip adjusted fully clockwise, adjustment knob at lowest setting -- would shut off motor with the kill switch or by choking.

 

[OptsyEagle]

I can't really say if the needle is OK or not. Probably fine.

On the compression test. Did you have both spark plugs out of the motor? If not run the test again with them out. If they were out it does seem like the numbers are a little low but since they are about the same on each cylinder I am concerned that perhaps it is the tester or as I said, both spark plugs were not removed or something like that.

Those twist grips can generate a lot of slop. For some reason it doesn't seem to affect their operation but I know my tiller moves about 1/2 inch before the timing plate starts to kick in, when the motor is not running. I don't know why running and not running makes such a difference but it seems to. Leeroy talks about slop in these tillers and how to fix it. Check out this link about 2/3rds down where it says:

"If your twist grip has a lot of slop in it"
http://www.leeroysramblings.com/John...leshooting.htm

Maybe it will help or you might see what might have caused it when you put the tiller back on the motor.