AQ130c riser gasket

wm_son

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Aug 12, 2009
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Background: New boat to me, motor yr is 1973. Recently replaced manifold and head gaskets due to water in oil. Upon start-up, pushed a freeze plug out and more water in oil. I'm thinking the increased compression from new head gasket coupled with the below diagnosis pushed it out and is forcing water into motor.

Diagnosis: it appears the existing gasket on the riser is not allowing water to pass through. Existing gasket is totally closed except for the middle exhaust hole (1 3/4" dia). I have the factory raw water system (open). Riser and manifold mating surfaces include the u-channel ports that are 180 deg offset from each other.

Question: is the gasket my problem? I'm showing the replacement gasket is basically closed also save for a 3/8" hole at the top. Any other ideas? Thank you. Gasket part no. 856028
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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the gasket you describe is for a closed cooled system. you have an open system

the gasket for an open system will have water passage holes in addition to the large exhaust hole in the middle.
 

wm_son

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Thanks Scott, do you have a part no. for the open system gasket? Part. no. 856028 only has one hole for what appears to be a water passage hole. Is this the correct part for an open system?
 

Scott Danforth

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go to volvopentastore.com and look it up in the exploded views for your exact motor
 

wm_son

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Aug 12, 2009
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Thank you Scott, I did, and it confirms the part number, 856028. What I find odd is that this gasket only has the one small hole to provide for water passage without any direction as to the placement of the gasket in regards to the hole. I was expecting to see a gasket that exposed more of the u-channel ports for water passage.

Any ideas on any of these peculiarities?
 

wm_son

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I'm considering making a gasket that does allow additional water passage. Hoping someone has some advice on making a riser gasket for an open system that allows water passage through the u-channel ports. Thank you.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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856028 is the proper one listed. you can try adding a few extra holes (i use a gasket punch set, however a shell casing from a .380 or .45 works) however you may pass too much water an not keep enough water in the manifold to keep it cool

I would look at your plumbing as the additional cooling water to the elbow is coming from the thermostat
5928_4.png
 

wm_son

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I put a hole at the top and one at the bottom. I'll have it out this wkend and will let all you all stars know the verdict early next week. teen-fo
 
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