Outboard boat engine questions???

[FireDrgn]

 Is there suppose to be a little water going down the shaft casing when engine is running?  Basicly down were the exhaust goes out and into the water...              If the answer is yes...  Can a bad water pump be allowing exhaust back into the water because of low water pressure?

Basicly i have exhaust gas comming out with the water that cools the engine.  I have replace the exhaust baffle gaskets and saw no cracks on the exhuast side...

thanks in advance to any one who might have some advice...




<S>

[Buzzard7]

What motor? I have seen some that have ports where exhaust and water sputter out in the rear. Been told that was to tell if the pump was working.

[FireDrgn]

Its a Mercury 40hp 4 cyl. 2 stoke.....

Normally there is no exhaust coming out with the water that cools the engine.    Now there is.... Since i saw no cracks on the exhaust side i am wodering where the heck the exhaust is crossconnecting with the water at.   I took the engine off of the shaft and there is a port that looks like water normaly comes out of.

Does Water normally goes down the shaft  with exhaust gas ?

[rogwar]

I believe that motor should be peeing a stream of water out of the side. Look it over carefully to find the little spout outlet. Sometimes the outlet can get plugged and you can use some heave fishing line, weed eater line or maybe a broom straw to unclog. Do not use anything sharp or metal!

DO NOT run again until you are sure because you could damage the engine. You may need a new water pump.

[FireDrgn]

Yes it peeess out the side where it is suppose to,but it has exahust gas mixed with it.  So there is definetly exahust gas pushing its way into  the cooling water somewhere.

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[68ZooM]

Sounds like the Gasket for the Powerhead could be bad, pushing exhaust gas into the water cooling chambers is a sure sign of that, the only other thing that could do that is a crack in one of the cylinder heads, but i would lean more to the blown Powerhead Gasket, run a compression check on all the cylinders that could also help in determining the problem, but i think its the gasket they get old and depending on the age and how the motor has been ran

[FireDrgn]

What is a Power head  gasket?   Is that the same as the cylinder head gasket?     If so, i have also replaced the cylinder head gasket.   SOOOOO this is not looking good for me....  I could see the cylinders when i had the head off. I did not see any cracks , but i will pressure check them.  I go down to Napa and see if they have a gauge for this.

Thanks

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[68ZooM]

Yea the Powerhead is the Cylinder head, are any cylinders getting water in them, all the plugs burning the same?   It's very importants that all the surfaces are perfectly clean and level ( using a straight edge check all surfaces) before you reinstall the head gaskets, if not then have a machinist resurface them, its hard to trouble shoot over the Net without first hand seeing whats its doing, but for now pressure check each hole, then go from there

[AAJagerX]

68ZooM prolly has it right on this one.  If there was an overheat, the cylinder head could be warped.  That can cause it to bleed exhaust into the water, even if the head gasket is new.  

[FireDrgn]

Rgr guys thanks alot.    I will take the head gasket back off and see whats up.






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[cattb]

At times a small crack may not open till there is enough heat to expand it.
Found this, was curious.
http://texasfishingforum.com/forums/ubbthreads.php/topics/4996669/Re_exhaust_in_cooling_water
http://texasfishingforum.com/forums/ubbthreads.php/topics/4996669/Re_exhaust_in_cooling_water

[TheBug]

I-boats forum is a great place to look for help with boating.  If your question isn't answered here, you will probably get some good help posting there. <S>


http://forums.iboats.com/forumdisplay.php?f=25

[fbWldcat]

2 stroke engines have done this to me a few times, normally it is a gasket loose or one time it was even where the oil/gasoline mixture wasn't correctly measured (God knows how). But I find that 4 stroke engines never really have this problem unless something important is wrong. Just my experience. Have you run it in a while? sometimes if you haven't run them in a while you get smoke in weird places, and you just have to start it up and let her run or a few minutes.

[FireDrgn]

At times a small crack may not open till there is enough heat to expand it.
Found this, was curious.
http://texasfishingforum.com/forums/ubbthreads.php/topics/4996669/Re_exhaust_in_cooling_water
http://texasfishingforum.com/forums/ubbthreads.php/topics/4996669/Re_exhaust_in_cooling_water

LOL  thats my post on the forums.  rogwar told me about them.

<S>

[FireDrgn]

I took the water pump apart and found one impeller missing .. Then got lucky and found the piece in one of the water holes when i took the exhasut baffle back off.. 


So i going to head in two directions at the same time here.   Impeller was 16.00  so i ordered one.   Im still going to check cylinder  compression and hope I dont find any cracks..

<S>   thanks  guys