Mercruiser 470 compression test.

[2fishy4u]

Ouch, yeah I would look into the cause of the higher temps at WOT. Mine will only go up 5 degrees at WOT. So I get 160 at all ranges below 4k rpm and when I go over 4k or WOT for extended periods of time my temp goes up to 165. So something is not quite right yet. Its easy to blow a head gasket on this engine if the temp gets too high.

 

[Kauaiboy206]

Ouch, yeah I would look into the cause of the higher temps at WOT. Mine will only go up 5 degrees at WOT. So I get 160 at all ranges below 4k rpm and when I go over 4k or WOT for extended periods of time my temp goes up to 165. So something is not quite right yet. Its easy to blow a head gasket on this engine if the temp gets too high.

Wondering if it has something to do with the lighter oil I put on there temporarily. I actually drained and put 10w40 temporarily and wanted to run it "flush" before I drain the oil and replace with 25w40. I wanted to make sure all the previous oil were circulated prior to putting in the proper oil. I changed the impeller, but didn't check my water pump. From what I read, the water pump or cam seal is bad when it starts dripping a/f from the weep hole and so far no signs of that. I still need to check my exhaust if it's draining properly and nothing is clogging it, but it seemed to be spitting out water on both holes.

 

[nola mike]

Nah, not the oil. You probably have the 3"heat exchanger. Might want to flush that if you haven't

 

[Kauaiboy206]

Nah, not the oil. You probably have the 3"heat exchanger. Might want to flush that if you haven't

Yepp i do have the 3 inch heat exchanger, everything is clear on it, all the tubes are clear and clean and see through.

 

[Maclin]

A common upgrade is to the 4 inch heat exchanger that the later models went to. If you keep running the temps on the edge and all components seem ok, that is the next thing to look into.