1973 18hp evinrude 18304a crankcase leak

[scuba_redneck]

Hey guys, I have been struggling with this 18 all day yesterday trying to get the halves of the crankcase apart. I have pulled all the bolts out and cannot get the darn thing apart! Does anyone have any idea of how to open this crankcase up? I need to reseal the edges because it is bubbling fuel out at idle. Any tips or tricks would be greatly appreciated. Pics when I get em to post

 

[oldcatamount]

Re: 1973 18hp evinrude 18304a crankcase leak

Hold the crankcase in one hand with the top portion of the crankshaft pointing out horizontally, (it's best to do this holding the crankcase off from the bench a little bit), take a soft faced mallet and lightly tap downwards on the crankshaft. Be sure you have removed the taper pin. It should show signs of breaking apart then. Just be gentle and take your time.

 

[scuba_redneck]

Re: 1973 18hp evinrude 18304a crankcase leak

Ok, where is the taper pin located? I have seen two pins that seem to be holding the crankcase together. Do they need to come out?

 

[F_R]

Re: 1973 18hp evinrude 18304a crankcase leak

Those are the tapered pins, two of them. They are to align the parts before you install the bolts. They muse be drivenout in the proper direction (Use a punch on the small end). And yes you need to remove them.

Furthermore, do you have ALL the bolts out? Including the two behind the reed plate? Once all fasteners are out it will almost fall apart--at least with a gentle tap on the crank. Don't force anything.

 

[scuba_redneck]

Re: 1973 18hp evinrude 18304a crankcase leak

So as of right now I have 8 bolts out and 1 taper pin. F_R, you mentioned two behind the reed plate? I am assuming this requires the reed plate to be removed and you are not talking about the two underneath the reed plate cover. Here are the pictures of where I am at now.

 

[oldcatamount]

Re: 1973 18hp evinrude 18304a crankcase leak

I would suggest you take the powerhead completley off the lower cowl. It'll make your job a heck of alot easier. Take off the intake cover and you'll see the 2 bolts FR was refering to.

 

[scuba_redneck]

Re: 1973 18hp evinrude 18304a crankcase leak

Awesome. Thanks alot guys. I will get that manifold off this coming weekend when I get back to my shop. That makes sense now that it did not want to budge with 2 bolts still holding it. I am assuming that I will have to replace the gasket between the intake manifold and the gasket between the powerhead and the exhaust housing. Is this correct?

 

[samo_ott]

Re: 1973 18hp evinrude 18304a crankcase leak

Yes, take the powerhead off as it's bolted to the cowling. And check for the two bolts behind the reeds. Btw, I sealed a 5.5 once that was bubbling from the outside using JB weld... If you don't want to take the entire thing apart, it worked for me... I tried several types of sealer first but it was the only one that worked.

 

[scuba_redneck]

Re: 1973 18hp evinrude 18304a crankcase leak

Well I would go the JB weld route, however I am already this deep in ole Bessie so I figure I'll just keep going and inspect the con rod bearings and the reed plate while I am in there.

 

[scuba_redneck]

Re: 1973 18hp evinrude 18304a crankcase leak

Ok guys, I'm back. I have ran into a little snag. I am having difficulty removing the powerhead from the leg. I have the bolts on the back of the powerhead loose, but I cannot for the life of me figure out how to remove the ones under the steering bracket. It looks like this thing is going to have to come off too. I have the LU dropped so I will not run into any problems with the driveshaft when removing the powerhead.

 

[Cap'n Chaos]

Re: 1973 18hp evinrude 18304a crankcase leak

My manual (for a 1972) says "remove 7 hex head screws attaching powerhead to exhaust housing" and references a picture which shows the location of 5 of them....do you have a manual?

 

[AlTn]

Re: 1973 18hp evinrude 18304a crankcase leak

take the 2 nuts off the "arms" of the steering bracket, then remove the "clamshell" clamp holding the lower shocks on the exhaust housing < just 2 bolts >, then you should be able to pull aside the steering bracket enough to gain access to those other ones holding the powerhead on

 

[milliesdad]

Re: 1973 18hp evinrude 18304a crankcase leak

There is one bolt with a larger head than the others. It is at the front of the motor, and you have to turn the motor to get a faqirly straight shot. you will need a 3/8th swwivel socket on a 1/4 drive ratchet.

 

[scuba_redneck]

Re: 1973 18hp evinrude 18304a crankcase leak

Update time. I was able to get the powerhead off thanks to you guys pointing me in the right direction. Once I removed the "clamshell" mount at the bottom of the exhaust housing everything went smoothly. I was able to clean up the powerhead halves with acetone and some rags made out of an old t-shirt. I resealed it with the permatex 518 anaerobic gasket maker and let it sit for 96 hours. Once it was allowed to cure, I ran it today and let me tell you guys what, this is the best this engine has ever run. I was only able to run it in a barrel today but was absolutely blown away at the smoothness of the idle now. I was able to set it and forget it. It finally seems like it will idle until I am ready to go. Thanks guys for all your help!