bourne1106

I recently bought a 1998 27' fountain 502 mpi. It has silent choice exhaust with Dana headers/manifolds when running boat with thru hull exhaust and running hard engine temp is right about 180. Within about 30-45 seconds you can smell the exhaust boots melt on the starboard side right after the y pipe. Checked hoses and riser doesn't seem to have any restrictions. Plan on checking temp with a temp gun this coming week. Any suggestions would be appreciated.

FIXX

iTrader: (2)

dana have had issues.. try looking for restrictors,,may need to take them out or install one on the opposite side that more water going to it so it forces the water through the side thats not getting enough..or you could just need a new inpeller,,cooling the engie ok but not pumping enough water to cool the exhaust..

FogduckerIII

iTrader: (-1)

Also check the angle of the rubber sections where they come off the risers, I had a set that burnt a hole through the rubber because the angle was wrong and the exhaust water supply was not equal all the way round? But as Fix says, check for restrictions first and then look at how the water is being introduced into the exhaust....

BUP

iTrader: (9)

The angle is the key factor like above said. if the angle of the exhaust boot(s) blocks or restricts water flow output from the exhaust riser in any portion, they will burn a hole from the inside out right thru the exhaust boot(s). Just seen this happening on a customers boat but with stock exhaust risers. All fixed up now. Also totally agree with the information posted here as well on top of.

bourne1106

It does seem like the corsa y pipe is pretty close to the tip don't know if that could be an issue.

bourne1106

Pulled off hoses going to oil cooler and found pieces of old impeler in the bottom hose. Should I be able to push a coat hanger through the vaines of the oil cooler?

BUP

iTrader: (9)

That's how we do it on the stock Merc apps if there is stuck debrie / impeller in the oil cooler or back side. We use old solid type shift cable inner core wires cut in long lengths pushed thru front to back of the oil cooler to push out pieces of stuck impeller blades and or debrie.

Also use long skinny needle nose plyers and short picks to grab them from the back side of cooler as well. Then we shine a dull lite thru the front side of the cooler and use an inspection mirror or inspection camera on the back side to help see if all broken impeller is out and the cooler is all clear of debrie. Sometimes we take the oil cooler loose from the bracket to help get them out for easier access and to be able to see better inside the cooler.

bourne1106

That's how we do it on the stock Merc apps if there is stuck debrie / impeller in the oil cooler or back side. We use old solid type shift cable inner core wires cut in long lengths pushed thru front to back of the oil cooler to push out pieces of stuck impeller blades and or debrie.

Also use long skinny needle nose plyers and short picks to grab them from the back side of cooler as well. Then we shine a dull lite thru the front side of the cooler and use an inspection mirror or inspection camera on the back side to help see if all broken impeller is out and the cooler is all clear of debrie. Sometimes we take the oil cooler loose from the bracket to help get them out for easier access and to be able to see better inside the cooler.

My oil cooler is mounted vertically so ur saying push Debrie out from bottom side to top side??

BUP

iTrader: (9)

follow your water cooling flow pattern output from the impeller housing and if the oil cooler is honeycomb internally then most likely your debris will be in that area and that section of the oil cooler. Very small material can get stuck in the honey comb section of the oil cooler. Also see sometimes very small pebbles & other small debris stuck in their as well especially boats that do not have sea strainers. if your impeller housing is internally scorn then that all needs to be changed out. Good luck

bourne1106

sry BUP still trying to get what you are saying try pushing debrie out with something stiff in the dirrection of normal water flow? or should i push the debrie out against normal water flow?