57' 7.5 head gasket, coils and sync

[ninhalo5]

Hi, I recently got a peek at the top of my pistons and they had a nice thick varnished carbon on them, so I decided to clean them up. I'm curious about replacing the Head gasket, does anyone suggest oiling the gasket or leaving it dry on these models? Most American vehicle HGs you put on dry but a good bit of European engines you put on some sort of lubricant so it can deal with the expansion of the head from heat, Im guessing dry for the American engine here.

Since it's been close to 20 years since I've had to deal with coils and points, I wanted to ask if there is any issue with the way I have routed my wires in the image attached. This route is the only way I can figure to not get ate up by the flywheel. But it's possible that wrapping a wire around the condenser could throw off the voltage, not sure if that would be the case here.

Thanks

 

[lindy46]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Install gasket dry. Magneto looks good.

 

[oldybutagoody]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

While you have the head opened up, I would suggest you check it for warpage. They are known to warp specifically in the area between the two cylinders. I hold a flat feeler gauge edge to the head and hold it up to a light source. if you see light leaking, your head is warped. You can lap it back to flat using a piece of 120 grit sand paper spray glued to a piece of glass and polishing it in a figure 8 pattern. It may take a while. My '57 18hp Fastwin had 0 compression on one cylinder because the head gasket burned thru due to the warped head. I replaced the head gasket but still had 0 compression. Had to get another gasket, lap the head flat and compression went up to 90 psi.
Ignition wiring looks OK to me.

 

[kfa4303]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Hi nin. Neat old motor. I just got done doing the same job on my '66 20 hp. No need for any sealant, or oil on the gaskets. You simply install them dry. You can get a new one along with any other routine parts you may need right here at iboats or at marineengine.com. I agree that the magneto looks pretty good too. Here are some great links that can walk you through a tune up from top to bottom. Just remember to only ever run the motor in a test tank (no muffs), use 24:1 fuel/oil mix and Champion J4C pugs. Per the previous post, you'll want to dress the head before you reinstall it. Use the pics below to perform the procedure.



?Start to Finish? - Part 1

3 HP Evinrude Lightwin Ignition System Tune-Up 1952-1967 (great iginition rebuild link. It's for a slightly different model, but all of the steps are the same)

5.5 HP Evinrude Johnson 1954-1954 Carburetor Tune-Up Procedure (great carb rebuild link)

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Thanks for that tip oldy, I do have pretty even compression, think it was around 60 psi in both cylinders, and the cylinder walls feel nice and smooth so hopefully that's all a good sign, but I'll go ahead and check that too. 2 minutes with a straight edge sure beats tearing it apart again.

Well, I reckon I'll get her all put back together this afternoon (provided my parts get here) and hope I can get her running again.

Thanks guys

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Thanks Kfa, that will help.

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Well, this should be interesting. I laid my straight edge that came with my micrometer down and there were gaps everywhere I laid it on the head, especially between the bolt holes. Then I laid my straight edge down on anything I could find and everything had gaps except for a piece of wood I have. So now Im thinking either everything I own is warped or amazingly that straight edge and board are warped perfectly in sync. Maybe the straight edge's gaps are being covered by some microscopic wood fibers.

Not sure what to think of it in this case...

 

[RogersJetboat454]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Well, this should be interesting. I laid my straight edge that came with my micrometer down and there were gaps everywhere I laid it on the head, especially between the bolt holes. Then I laid my straight edge down on anything I could find and everything had gaps except for a piece of wood I have. So now Im thinking either everything I own is warped or amazingly that straight edge and board are warped perfectly in sync. Maybe the straight edge's gaps are being covered by some microscopic wood fibers.

Not sure what to think of it in this case...

Not too uncommon for those heads to have multiple low spots.
Best to dress the head. 120 grit sand paper is WAYYY to course IMHO. Some sheet's of 300 and 600 should knock down the high spots, and put a decent finish on it.

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Perhaps I should start a new thread on this one, but do any of you have experience Synchronizing the carb/magneto?

I just read this must be done after servicing the magneto/carbs and this might have been my entire problem with the way my engine was running.
I have a manual, but it's not making much sense to me. My engine is listed as location 7 adjustment note 1

The instructions in the manual say

"The No. 7 Location
6- Engines referenced to No.7 are to be
adjusted to the CENTER of the mark. To
obtain this position, the cam, or the cam
follower, (depending the type of engine being
serviced), is to be adjusted until pickup
is at the proper location and the throttle
shaft just begins to move.
7- Movement of the shaft can be exaggerated
by attaching a short piece of stiff
wire to an alligator clip; grinding down the
teeth on one side of the clip; and then
attaching the clip to the throttle shaft, as
shown. The wire jiggling will instantly indicate
movement of the shaft. The actual
adjustment is accomplished by ONLY ONE
of two means, depending on the engine being
serviced. Check the Appendix for the adjustment
to be performed. The reference
numbers are listed in the Appendix under
Primary Pickup Adjustment Note.
8- Per Note 1 in the Appendix, loosen
the two screws under the armature plate
and move the primary pickup inward or outward
to meet the follower.
9- Per Note 2 in the Appendix, loosen
the center screw on the throttle lever and
move the lever inward or outward to match
the line on the cam. This applies only to the
9.5 hp models."

The pic in the book is horrible and is of a different engine. I cannot make heads or tails of what they are talking about.

Thanks

 

[lindy46]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

In layman's terms, advance the throttle and when the cam roller (follower) hits the mark scribed on the cam, the throttle butterfly should just start to open. Loosen the bolts on the underside of the cam and adjust to make it so.

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Is this what I'm looking for? Line the yellow arrow thingy up with 1 or between the 2 lines ( blue and red arrows)

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils and sync

Re: 57' 7.5 head gasket and coils and sync

Ok, so I took a peek inside the carb and slowly twisted the throttle, the butterfly began to open with the arm on the carb about 1/8" from the first line on the plate. The follower(?) curved thing mounted under the plate; was pushed as far in as it would go. Moving it out will open the butterfly even more. What should I do now?

Thanks

 

[nwcove]

Re: 57' 7.5 head gasket and coils

Re: 57' 7.5 head gasket and coils

Is this what I'm looking for? Line the yellow arrow thingy up with 1 or between the 2 lines ( blue and red arrows)

edit

 

[nwcove]

Re: 57' 7.5 head gasket and coils and sync

Re: 57' 7.5 head gasket and coils and sync

Is this what I'm looking for? Line the yellow arrow thingy up with 1 or between the 2 lines ( blue and red arrows)

nope.....that isnt what you are looking for! there should be a mark by the yellow arrow, for get the red and blue arrows.

 

[F_R]

Re: 57' 7.5 head gasket, coils and sync

The red and blue arrows are timing marks for setting the breaker points with a light or meter.

 

[ninhalo5]

Re: 57' 7.5 head gasket and coils and sync

Re: 57' 7.5 head gasket and coils and sync

nope.....that isnt what you are looking for! there should be a mark by the yellow arrow, for get the red and blue arrows.

Oh, I think I found it, there is a tiny mark on the cam thing itself right past the weld and under the part number, just to the left of the bolt hole. When I turn the throttle to start it's lined up with the carbs throttle arm. If that's not it then the mark must have been painted over, because there sure are no other marks anywhere on that side of the engine.

 

[lindy46]

Re: 57' 7.5 head gasket, coils and sync

The line is scribed into the cam, not just painted on. Should be pretty obvious.

 

[ninhalo5]

Re: 57' 7.5 head gasket, coils and sync

By George I think I've got it. Got it all put back together, and boy was rebuilding that recoil starter a mother... But anywho, I'm now getting really high RPMs where I wasn't before. Engine is now revving like a dirt bike, smelling like one too
Here's to hoping the rain holds out tomorrow so I can give her the river test. Least I purchased a 40lb minn Kota today, rowing the Jon last week really sucked

Thanks guys for the help, hopefully I can post some good news tomorrow and be able to sandbag in the forums for awhile.

 

[nwcove]

Re: 57' 7.5 head gasket, coils and sync

just a tip.....never rev an ob motor to wot in a barrel/bucket or on muffs! or your next post may read " why did my motor throw a rod through the block!"

 

[ninhalo5]

Re: 57' 7.5 head gasket, coils and sync

just a tip.....never rev an ob motor to wot in a barrel/bucket or on muffs! or your next post may read " why did my motor throw a rod through the block!"

Yeah I didn't have it WOT, I revved it about 1/2 - 3/4 throttle and the RPMs were high enough for me to say woah, too fast. Now before, I could open it WOT and the RPMs were probably about 1/4 throttle as it is now.

Keeping my fingers crossed the thump during WOT on the river is fixed now, if not, I guess it'll be time for me to take the dog for a walk.
Originally I found 1 coil wire was ate up and barely holding on, which got me started in this endeavor. I replaced the coils, condensers, plug wires, points and rebuilt the carb because the lower packing sprung a leak. Got all that put on a week ago took it back to the river to tune and it ran horrible (great in the bucket, horrible away from home). So I was working on it at the river, then my recoil spring snapped. Now everything is set up the best I can get it. Hopefully it'll do good in the river this time, or I might just have to tie a rope around it and make me a nice fancy anchor lol.