Mystery Bolt and New Gasket?

lent0n

Seaman
Joined
May 20, 2022
Messages
66
Hi all,

Just winterized my 1976 75hp evinrude after a great season.

Noticed two things while I was fogging the engine.

1. Some water seeping out - you can see in the video linked - https://photos.app.goo.gl/6tq15RdjhNKP8uqi7

I'm assuming that it's safe to say it's worth replacing the cylinder head and tank cap gasket before going out next season? I was planning on checking out the thermostat before next season started to make sure it was all good and likely replace it just to have some peace of mind. Is there any other maintenance I should do while I'm in there or concerns I might not be aware of? Motor ran like a top all season long and this is freshwater only.

2. A mystery bolt appeared on the driveway and I can't see to figure out where it came from and I've never seen one that looked like this before. Anyone know where it's supposed to go? It looks engine related to me. https://photos.app.goo.gl/6tq15RdjhNKP8uqi7
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,633
Looks like giggling water drops and not actual leaks....could be wrong I guess. Try a torque wrench on the bolts? (Not sure you need to)

Bolt picture is the same video again. Repost bolt picture.
 

cyclops222

Lieutenant
Joined
Mar 21, 2024
Messages
1,284
You do not have enough engine experience to just replace a cylinder head for no real reason. Pick on something else to keep busy.
 

cyclops222

Lieutenant
Joined
Mar 21, 2024
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1,284
Having a bad medical time. Did not mean to be so critical.
 
Last edited:

lent0n

Seaman
Joined
May 20, 2022
Messages
66
You do not have enough engine experience to just replace a cylinder head for no real reason. Pick on something else to keep busy.

racerone is correct I'm just talking about the gasket, that's not the type of thing I would do on a motor I plan on using in the near future, I'd get a beater to learn on. Hope you feel better soon!
 

lent0n

Seaman
Joined
May 20, 2022
Messages
66
Looks like giggling water drops and not actual leaks....could be wrong I guess. Try a torque wrench on the bolts? (Not sure you need to)

Bolt picture is the same video again. Repost bolt picture.

Giggling water droplets?

I believe the gaskets are less than 2 years old and the previous owner was a mechanic who did quite a bit of work to the motor, he sold only because he needed a larger one for his newer boat. I can definitely just re-torque them in the spring. I'm not looking to make work where it's not needed, but the best time to work on the boat is before the season starts so I'd rather figure out what I need now rather than later.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,809
Replacing the head gasket on a motor like that is a simple job.-----Just 22 bolts.----Refinish ( flatten ) the warped head.----Replace rubber grommets on the poppit valves.----But if it is a salt water motor it might be a challenge.
 

lent0n

Seaman
Joined
May 20, 2022
Messages
66
Replacing the head gasket on a motor like that is a simple job.-----Just 22 bolts.----Refinish ( flatten ) the warped head.----Replace rubber grommets on the poppit valves.----But if it is a salt water motor it might be a challenge.

Thankfully it's freshwater. I guess I'll have a look in the spring. Thankfully since it's been off somewhat recently I don't expect a lot of seized bolts thankfully. I would be surprised that it would be warped but, can't argue with the evidence in front of me and since it has to come off anyway to replace the gasket, might as well verify.
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,633
Bolt is a shouldered bolt with a plastic bushing. Definitely could have come off your motor or was sitting down in the lower shroud from an earlier repair event. Thoroughly look around your motor.

I saw what looked like a wet motor with giggling droplets. Never saw water dripping or spraying out.
 
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