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View Full Version : new mc owner has lots of problems/questions


joniron1
02-17-2009, 12:43 AM
I just bought a 89 prostar 190 from my wifes cousin,the boat had sat up for 5 years.they told me they removed the thermostat because it ran hot after a new impleller was installed.i found alot af impeller debris and removed it and replaced the thermostat they had(its 180 deg).it almost immediatly started getting hot.so i took the thermostat back out,in the process of doing so my buddy noticed some water trickling out of some major corrosion on the side of the head .also while cruising 30 mph then dropping the hammer steam comes out of the exhaust for a few seconds and seems to be more from the side with the bad head.i cant afford to do much right now and she purrs like a kitten,so im thinking of getting a few tubes of jb weld and applying like bondo,to try to get a few rides in this spring then get a reman motor later .another option is to replace the heads but it would seem to me like the block could be corroded as well.a freind has some gt40 heads but he said there are different types. which would fit the indmar 351?what is the difference between a marine and auto engine.any thoughts on this would be appreciated.

mayo93prostar
02-17-2009, 07:24 AM
the leak could just be a gasket on the exhaust manifold. try replacing them before going deeper into engine. the thermostat should be a 143 degree one. check www.skidim.com for these parts, or your local dealer. not the temp difference in the thermostat, the 180 or 190 is typical for a car/truck. the 89 era marine engines had 143 degree thermostats. change the impeller again to be safe. good luck, post pics.

TMCNo1
02-17-2009, 08:14 AM
One thing that needs to be checked first, is for possible blockage by debris on the raw water inlet side of the transmission cooler.

joniron1
02-17-2009, 01:40 PM
water is actualy coming out of the head itself,the head gasket and manifold gasket leaks some as well.i think chunks of corroded head are creating a blockage in the head itself.im going to get the right thermostat and try it,but what would happen with no thermastat?i was thinking it would lower pressure and maybe reduce the leakage .the head is trash no doubt about it,so if i can run it a few times before i can get a reman long block(i was quoted $1350 +199 shipping from a marine machine shop in fla ) that would be great .worst case scenario seems to me is i finish off a neglected motor.i live very close to the canal i wakeboard on and have friends with boats nearby so im not really very concerned about breaking down.but i may be able to replace the heads but im leary of putting money into the head replacement if the block turns out to corroded as well.

Gamble
02-17-2009, 03:35 PM
............if it were me, I'd fix it correctly before taking it out. You know you have a problem, get it fixed, and go on.............otherwise, you're just begging to have a bad experience on the water.

joniron1
02-17-2009, 10:42 PM
i was told today marine engine blocks have a high nickel content to resist corrosion.does anyone know if that is correct?if so maybe i can replace the heads.if so does anyone have any info on which gt40 heads would work on the indmar 351?as far as a bad experience on the water, i could walk to my house in an hour from anywhere on the canal i ride on.

VOLFAN
02-17-2009, 11:09 PM
as No1 said take the tranny cooler off and all those hoses. make sure there is no remaining pieces of the old impeller in there also! just takes a couple to block the flow of water and make it run a lil hot.

FrankSchwab
02-18-2009, 12:36 AM
With no thermostat, the engine will run OK. However, it'll probably run rich, which will create deposits, thin the oil, etc. So, for the purposes of a test run, going without the thermostat would be fine. For long-term usage, you'll need one.

/frank

denverd1
02-20-2009, 03:56 PM
It will take the engine a lot longer to get to operating temp range. I was told that the rings won't seat down properly if it not allowed to heat up with the t-stat closed. my 351W was running alittle hot last year, so I left it out. i'm getting the overheat issues sorted out and will likely run a 143* this yer.


Frank, I'm curious. How does cooler temps create a rich condition?

jeverett
02-20-2009, 04:08 PM
It will take the engine a lot longer to get to operating temp range. I was told that the rings won't seat down properly if it not allowed to heat up with the t-stat closed. my 351W was running alittle hot last year, so I left it out. i'm getting the overheat issues sorted out and will likely run a 143* this yer.


Frank, I'm curious. How does cooler temps create a rich condition?

Cooler temps will create cooler intake and inoptimal atomization of fuel.

denverd1
02-20-2009, 04:17 PM
That makes sense.