1973, 18 HP, Overhaul....

[perkdp]

Hi folks.... my first time deep inside an outboard. I have 73 model 18 hp evinrude model 18304A. I have one of those generic service manuals but its not real clear, on some things, to a rookie like me. <br />1) does the high side of the piston go against or opposite the exhaust ports ? <br />2) this engine has what the parts catalog calls carbon seal on the botton of the crankshaft. is this seal supposed to turn with the crank or ay lock down by the crankcase halves ? <br />3) don't know how to ask this one.. the top (flywheel end) of the crank has 'can' left between the bearing/oil seal and the end of the casing where the coil plate slide over. is there something supposed to go in there to fill up that 'can' ?

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

1) Have a look at your other post. High side toward the intake.<br />2) The seal is supposed to turn with the crank. The actual rotating seal is between the bearing face and the carbon itself. It's lubricated by the oil that collects in the bottom of the crankcase. The quad 'o-ring' seal is static.<br />3) The oil seal should be pressed in flush with the top of the bearing shell. It sounds like someone pushed it in a whole lot further. You'll need a new seal to correct this, as you can never remove those seals intact. Probably it's worth while for a new seal anyway.<br /><br />Keep em coming!

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

I put the new seal in on the top crank bearing but this can is after that seal. It is formed by the crankcase halves making a hollow dome for the coil plate to fit over. Looking down at it from the top just looks like something is missing. I have everything in place that's shown in the parts diagrams at www.evinrude.com <br /><br />2) Thrust washer (brass against crank throw) <br /> bearing (hole on dowel)<br /> o-ring around bearing inside the case<br /> o-ring inside carbon seal<br /> carbon seal sets against bearing face<br /> washer <br /> spring <br /> washer<br /> retaining ring

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

Oh, I get you now. No, there's nothing that goes in there, just a great big hole around the crankshaft, with the bearing & seal at the bottom.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

yep... that's what i see. it's kinda hard to explain. sure don't look right to me. <br /><br />Thanks for your help Paul

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

I have the pistons/rings, rods/bearings(torqued), crank/bearings all back in the case and snugged down for a fit test. How easy should the crankshaft turn with all this in place ?

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

It'll turn easily by hand with the flywheel in place, but it'll be too difficult to spin the crankshaft alone by hand. You should feel no rough spots. The only real drag you should feel is from the piston rings.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

I feel the ring drag. No rough spots. Can't turn crank by hand but can make it all turn just by pushing on the pistons with hands (don't have the head on yet) or wrench on flywheel nut. I'm concerned that its too loose even though I checked the ring end gaps to be well within tolerance at 7 thousanths. (i read the book to say end gap range 5 to 15 thousanths on 9.9 and 15 and 7 to 17 on 20hp. the book I have don't specificly mention the 18hp). I guess I'll find out when I get it all back together.

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

Sounds about right. What's the condition of the cylinder wall? Freshly honed, glazed, rusty? It ought to be the former and it makes a big difference on how it'll feel. I take it those are new rings if you're measuring 0.007"<br /><br />It's 7 to 17 on the 18hp. There's no real difference between it and the 20hp. 9.9/15 is a completely different beast.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

New rings. Freshly honed (glaze breaker)<br />Cyliner walls look good to me. <br />Thanks for the tip on 18 vs 20 as the torque specs on the rod caps are quite different between the two. 9.9/15 = 48-60 inlb vs 20hp 80-110 inlb(if i remember correctly). Had trouble with torque wrench and tightened rod caps a bit tighter than 48-60 inlb I believe. But they're probably real close to the higher numbers. Getting a new wrench and plan to re-check the rod caps. <br />Thanks Paul for all your input.

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

Your welcome. I'm glad I can help.<br /><br />Sounds like you have it under control then. Connecting rod bolts should be 180-186 inch/lbs. Do not try to torque these with a ft/lb reading torque wrench because they're normally very inaccurate at the low end of their scale. For outboard work you're stuck buying two, one for the flywheel and one for the rest of it. Sometimes the con-rod bolts need a ft/lb wrench, but not in your case.<br />The inexpensive beam-bend type ft/lb wrenches are usually pretty accurate, and will suffice for occasional work. They're just kind of a pain to use.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

The Kill switch.... wires were real bad shape... soldered some replacments on the best I could... I just want to be able to stop this thing in case it tries to run away with itself the first time I start it. <br /><br />So, this thing being in buckets when I got it,, where do the two wires coming from the kill switch plug in ?

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

Each of the two wires from the kill switch connect to a point terminal. So when you push the kill switch, the points are shorted together. That stops spark in both cylinders. They go up through the grommeted holes in the armature plate.<br /><br />Runaway is often the symptom of too hot an engine or some source of autoignition. Too hot a spark plug, glowing carbon deposits, that sort of thing. In those cases the kill switch does not help. Best thing to do is to hit the choke and pull the gas line. But on a well maintained engine it'll probably never happen so don't worry about it.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

Well, I'm getting close with old motor. <br />I put the magneto and flywheel on last night and bench tested for spark. (I'm glad I didn't have hold of the wire when I pulled the rope.) Coils, condensers, wires, all look good. <br /><br />Does anyone have some tricks to make spark timing, throttle, spark advance easy to get right ? <br /><br />If I can get those asjustments right and the caburator is not too gummy I see no reason why this former bucket of parts won't fire up and run well.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

Got it started last night ! <br />Put in barrel, hooked up the gas, choked it, pulled the rope 4 time and it fired, choke in, 4 more pulls and ran. <br /><br />Still have some fine tuning to do.... shakes at low idle. But, after running about 10 minutes it starts on the 1st pull. <br /><br />The throttle is hard to turn though. I notice the coil/magneto plate was hard to slip of the crank case and not easy to turn by hand before linkage was hooked up. <br /><br />Does anyone have an idea what's causing the bind and how best to make the throttle and magneto plate turn easier and smoother ?

 

[itstippy]

Re: 1973, 18 HP, Overhaul....

It should turn smoothly and without wiggle. Gotta be smooth before you hook up the linkage. You will not be happy until you pull the recoil, pop the flywheel, and have another go. Be sure to do this Joe Reeves trick if you have any wobble, which 90% of the time you will have:<br /><br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=020981#000001 <br /><br />Also make sure your plug wires are routed correctly behind the throttle control lever. They bind if not routed correctly.

 

[perkdp]

Re: 1973, 18 HP, Overhaul....

Well it finally runs pretty well.<br />Carb kit did the trick after the other problems encountered. <br /><br />If interested...see other posts...<br />Coughing at idle <br />Magneto / Coil plate -- binding (or search this forum for perkdp) <br /><br />Thanks to all who have passed information my way !

 

[Paul Moir]

Re: 1973, 18 HP, Overhaul....

Glad to here got it fixed. Sounds like you've got it 100% up to date now.