Feelin’ HOT HOT HOT!

[akorcovelos]

Ok, had a major face palm event today...finally found time to put the circ pump back on.

Plugged the bypass and put a new 160 thermostat in. Used the opportunity to clean the front of the engine and used my paint pen to refresh the timing marks.

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[akorcovelos]

Well, feeling pretty good I put it on the muffs and low and behold, still no water...

Everything but the coolers were new, and the coolers were clear and leak free. Even though I pulled the sea pump once and it looked fine, I decided to replace it anyway. I pulled the “old” impeller out, still looked brand new, EXCEPT when I put the new and old side by side I saw the problem instantly. Not sure how, but the impeller has seized inside the housing, and the pump shaft stripped out the impeller hub. You can see in the pics below that the D hub is now an O on the old one. I have never seen a failure like this.

Life lesson for today, if you pull the sea pump off, never put it back on, even if it looks brand new...put the new pump on and bam, nice strong flow of water out the exhaust and it ran for 15min on the hose and never got close to over heating.

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We’re hitting the water tomorrow for a sea trial, but I’m sure it’s fixed.

[dustinm]

Please put that bypass back in. On a BBC there is no reason not to keep it.

[Big Block Power]

Please put that bypass back in. On a BBC there is no reason not to keep it.

Akro why would you block it? Merc put it there for a reason.

Glad it's running normal temps though.

[akorcovelos]

The bypass is unnecessary on marine engines. Every high power marine engine either deletes the bypass or deletes the circulation pump all together and runs a cross over pipe. The rubber elbow was ready to fall apart, and it’s just another place to leak. I should say I drilled 4 1/8” holes in the thermostat to allow for some flow before the thermostat opens. Not breaking new trails here, all the high performance builds around here do it.

[dustinm]

take this for what its worth as Im not trying to run you down, quite the contrary. those HP builds aren't built for longevity - season or two before freshening, some not even that. your engine will warm up more evenly (lessen chances of scored pistons) not to mention lessen the pressure on your thermostat. Its different when you delete the entire GM waterpump as the volume isnt there.

[akorcovelos]

take this for what its worth as Im not trying to run you down, quite the contrary. those HP builds aren't built for longevity - season or two before freshening, some not even that. your engine will warm up more evenly (lessen chances of scored pistons) not to mention lessen the pressure on your thermostat. Its different when you delete the entire GM waterpump as the volume isnt there.

Eh, I’m not worried about it. I’ve got buddies that have been running no bypass for years without issue. Boat ran great today, didn’t miss a beat. Didn’t have my GPS out but I hit 62 on the lie-o-meter, which is faster than I’ve ever seen it.