Ouch hot exhaust - help!!!!

Spike2450

Cadet
Joined
Aug 26, 2007
Messages
21
Hi
1998 V8 - 5 litre Mercruiser - non injection, raw water cooled.

After noticing a temp difference at the exhaust riser whilst at idle, i took her for a spin tonight to ease my mind and when i checked her the starboard exhaust riser was literally steaming hot and the bent downpipe pipe that runs after the exhaust riser was so hot the paint was smoking!!!
With lots of steam out the back, engine temp consistent 175!

The Port side riser and manifold was fine.

I'm going to strip her tomorrow, can anyone give me an insight as to what to look for, especially any set procedures.

Could this be a thermostat or a probable corrosion / blockage problem. With the port side being ok does the stardboard tend to get more corroded.

I checked the large water hose on the starboard side anyway and noticed that the internal spring was badly corroded, when purchasing does this spring come with the hose and if any bits of the spring have broken off where would they end up.
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: Ouch hot exhaust - help!!!!

There's no cooling water getting to the starboard exhaust.
Start at the thermostat housing, remove the hose to that exhaust. Look in housing, clear hole if blocked.
If ok, blow into hose. Blocked? Remove other end and try again.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,588
Re: Ouch hot exhaust - help!!!!

Could also be the riser itself is blocked up. When was the last time the riser was removed to inspect the riser/manifold area to check for corrosion?
 

Spike2450

Cadet
Joined
Aug 26, 2007
Messages
21
Re: Ouch hot exhaust - help!!!!

Hi
Thanks for the replies, ill check the pipes running from the thermostat housing and i will pull the Elbow after draining the her.
I've just purchased the boat and was on sea trials,
Is there much in the way of water channels in the manifold as well, i.e. will it be obvious when i pull the riser where the problem is?
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: Ouch hot exhaust - help!!!!

It will be obvious, since you do have water to the port side. If you find coolant passages that are bone dry, back up to the previous connection.
 
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