Hey guys i got my new motor n today and fired up and timed great. But the driverside exhaust (thu hull) is steaming when gets warm Im kinda confused. So any help will b great. Ps also i dont no if impeller bad to but it wasnt get n hot about 150s thanks

It may help us out to know What engine do you have? and what side is hot starboard side [Right], Port side [Left]? Thank's

Maybe a picture how it looks like ,,on the transom!!

And what is it thats steaming???? the outside of the pipe or at the transom ??

Its the starboard side and the motor is a 454mag that i built up new cam intake carb ext. It is the water coming out out the exhaust the water is hot and steam n i have silent choice to so the water dumps down the y pipe to the transom and out the sides. I put on a new mercruiser thermo to i went from 6 hose to the 4 hose and also bought used imco thumper manifolds. I also shot the thermo and it was any were from 140 to 160f and i was also run n on earmuffs so if that makes a diff. I just dont know it never did it before.

I had the same problem at the worlds ladt year and burned a piston!!!!
It runs to hot,,( in my case it was the timing ) was way to high !!!
But then also my valves where touching the pistons ?!

Hope that helps !!

Head gasket ,cracked head,or crack in a cylinder on that side.Pull the plugs on that side and see if any look different than the others.

even if i just got the engine back from the shop complete refresh and they put it together from oil pan to intake. I hope that wouldnt have missed something like that. I just pulled the impeller out of the sea pump and nothing gone but 3 fins were cracked and from the looks of it could have been folding over when runing so could this have cause this problem due to like low water press or not? Geting to close to memoial day weekend...........

My engine came from the shop as well,,,,,i hope it was not the same shop. LOL

But i would check it ,,cam timing, timing,valves ,,,and so on !!
I say it can be !! I did not say thats your problem !
But definitely running to hot !!!!!!

o also put msd blue box complete ign. and the shop set adv. in the cam also so i guess ill grab a new impeller and go from there. thank you o now that i think about it when i would rev up to around 2000 rpm the steam would stop would that b cause to the pump moving faster idk and what should be normal temp.

OK,,,,,,here is your problem,,,i bet u used a digital timing light !!!!!!!!!

NEVER DO THAT ON A MSD BOX.

I bet your timing is @ 45 + !!!
Exactly what happened to me !!!
Use the cheapest 30 bucks timing light on a MSD !!!!!
Go check it and u be surprised !!
Hopefully u did not lean it out yet !