#$@^!^%! Broke three head bolts on my 3hp evinrude

Tim B(tbrom)

Tim B(tbrom)

Active member
I noticed my 1961 3hp evinrude was running hot. I was getting good flow up to the check screw but the water wasn't making it around the cylinder. I decided to clean the path. While attempting to remove the head, I backed three bolts out with ease the other three had no temper left. I put little to no pressure and the first one broke. Same with the second and I felt the third going so I cut the head off to have some threads to play with. I got PB blaster and have been soaking them. I also bought two left hand twist drill bits. If anyone has experience I would love some advice!
 
I went through this last week on my 150 Yamaha. I was having a over heat alarm. Decided to pull water jackets and heads. Ended up breaking one of the bolts off in the block. Tried easy out with no luck. I had to drill out the bolt and re tap with a bottoming tap. Pain in the neck but it all worked out.
Good luck, Jeff
 
PB Blaster is good but check out this link for an even better penetrant ATF/ Acetone 50/50.
http://www.rimfirecentral.com/forums/showthread.php?t=469335
 
PB blaster worked on two with left a hand drill bit. I drilled and tapped the third. I got the motor back together. I will gas it up and give it a go tomorrow. I am waiting on a new head gasket but the old one was intact. Fingers are crossed and I think it will cool now. Does anyone know how hot these little motors run? Should I be able to touch the head without getting burned?
 
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Should I be able to touch the head without getting burned?
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Tim,

I would say no don't expect it to run that cool at the head. I don't have any facts and figures for that motor but for reference, my 60hp four stoke has a thermostat which opens at 120 degrees. I would expect an older two stroke to run much hotter that that. Even being a water cooled engine, I'm guessing it's going to be around 160 degrees at the head.



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Make sure you pull the exhaust cover and check the gasket. If exhaust leaks into the water jacket it will overheat like crazy. As far as head temp I just watch for changes. An infrared heat gun is a great tool that isnt real expensive. Make sure the exhaust cover may be warped so check on a sheet of glass or surface plate. Good Luck.
 
Thanks guys. I know it is going to run like crap until I get all of the PB blaster out of it. I want to get it running tomorrow and take it out to the lake and run it wide open. That seems to get it cleaned out.
 
It is still running hot and I noticed there is no water tube grommet. All this monkeying around and I bet the pressure with the grommet would have cleared the port.
 
Is there a good flow of water "out"?
For any outboard I expect exhaust water to be warm but not hot.
I wouldn't take the head off of even a 3 HP OB myself. When I had an overheating problem w/my mid 90s vintage 3 HP Evinrude I noticed that the mechanic "faired" the head on glass (very flat) with sandpaper in case heat warped the head.
If the water intake is clear, head not warped & impeller in good shape you should be fine.
 
Is there a good flow of water "out"?
For any outboard I expect exhaust water to be warm but not hot.
I wouldn't take the head off of even a 3 HP OB myself. When I had an overheating problem w/my mid 90s vintage 3 HP Evinrude I noticed that the mechanic "faired" the head on glass (very flat) with sandpaper in case heat warped the head.
If the water intake is clear, head not warped & impeller in good shape you should be fine.
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There was a great flow out it was going strait from the pump into the exhaust port and out. Without the grommet there was not enough pressure to circulate water around the cylinders.
I guess I am old, I don't really think of a mid 90s motor as vintage.
 
Just some PM recommendations gang.

We here in the salt obviously never get those kind of lifetimes out of motors but we have learned a few tricks to ward off corrosion & keep things lubricated.

Pull the cover & spray the entire motor with brake cleaner.

This will remove a all dirt, grime & salt build up on the motor.

Blow off with an air compressor with an attached moisture element or drain water from compressor through peacock on the bottom.

Start motor & run up to normal op temp.

While running, spray entire motor down with Corrosian Block (blue stuff).

DO NOT use the CRC (brown stuff) because it will trap moisture & make things worse.

The motor is going to smoke like Hell but the heat will help the CB absorb into the motor.

Any parts like connections & rubber hoses that due not get hot, just leave them be!!!

It moisturizes the parts & creeps into the threads of the bolts.

I learned this from my OB mechanic that teaches at the marine mechanics institute in Orlando.

I have a (19) nineteen year old Evinrude that when u pull the cover off, it still looks brand new.

I also use the same process on my mud motors & airboat motor.

Good Luck!!!
 
One other thing!!!

I know I've stated it before but after every couple of tricks, I disconnect the hose at the wall, pour a cup of Dawn into the hose & run it through the engine.

It breaks down the salt & other junk that blocks up the passage ways keeping the motor running at peak performance.
 
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