350 mag water leak

[JayhawkCurtis]

Getting the boat ready for the water for the first time this year, fired her up on muffs for the first time since winterizing last fall, and I have a water leak around that front port lower blue drain plug. The winterizing instructions call that plug the "distribution housing" I tried snugging the blue plug and it jumped threads like it is stripped or the housing is cracked. Tried a new plug and the same thing. put a little fatter o-ring on, and snugged to just before I felt it was going to jump, and it is down to a drip. Its not going to keep me off of the water, but need to have a remedy. I have looked through the parts breakdown, and can not find that housing.
Thanks for the help. The top left pic

 

[Espos4]

Getting the boat ready for the water for the first time this year, fired her up on muffs for the first time since winterizing last fall, and I have a water leak around that front port lower blue drain plug. The winterizing instructions call that plug the "distribution housing" I tried snugging the blue plug and it jumped threads like it is stripped or the housing is cracked. Tried a new plug and the same thing. put a little fatter o-ring on, and snugged to just before I felt it was going to jump, and it is down to a drip. Its not going to keep me off of the water, but need to have a remedy. I have looked through the parts breakdown, and can not find that housing.
Thanks for the help. The top left pic

They crack under the threads. The portion that cracks faces down toward the bilge floor. If you can get an inspection mirror down there, you’ll see as you tighten the plug, the crack will open up.

 

[JimG]

Yep, seen this before... fairly easy to replace. I believe there are only 2 different distribution housings for your engine, difference being Horizon engines (antifreeze cooled) or raw water cooled.

 

[JimG]

This one is for raw water cooled:
https://www.amazon.com/Distribution-863631T1-863802T2-863444T2-Mercruiser/dp/B093G6GFMD

 

[JayhawkCurtis]

Wow thanks for all the responses, I think it began leaking toward the end of last year, I started picking up water in the bilge that was more than normal. I just ordered the part Jim linked.
Thanks again

 

[Espos4]

Wow thanks for all the responses, I think it began leaking toward the end of last year, I started picking up water in the bilge that was more than normal. I just ordered the part Jim linked.
Thanks again

Always keep a fresh o-ring on that particular drain plug. That way it will seal with very little pressure needed. Once that O-ring gets older and a little stiff, it’ll need more force before it seals and stops the drip. That is when that housing it is likely to break.

 

[dan313]

This same issue happened to a friend of mine. It was leaking at the blue plug. He tried a stainless plug and it made it worse. Turns out the Water Distribution Housing had a crack. Changed the housing all good now.

 

[Bt Doctur]

 

[Soulshine]

If possible, snug a small hose clamp around it before inserting the plug. This should prevent future cracks.

Plastic parts are why I prefer older boats.

 

[JayhawkCurtis]

Wife and I came camping this weekend, first weekend alone on the lake this year, after we put the boat on the water it popped the engine hatch and the leak had gotten quit a bit worse. So I decided it was time to put on the new housing. So at the campsite this morning before it got to hot I changed her out. Hardest part was getting the old hoses off the old housing.