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Starboard running way hotter than port

bayliner_02

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"Gentlemen. Im running an 02 M

"Gentlemen. Im running an 02 Merc V6.When running, starboard side appears to over heat. i have recently stripped down engine and inspected all of the main components i could think of (impeller, water pump, manifolds, risers, thermostat) i have replaced both manifolds and risers. both the impeller and water pump appear to be in good condition and the thermostat is fine. when flushing the engine steam emanates from the starboard side. also, the starboard riser is running very hot compared to the port side.(not sure what temp it runs to but i can only keep my hand on riser for about 10sec and then its too hot where as port side i can keep my hand on it all day!)
Also, when flushing out very little water appears to be flushing through on starboard side compared to port.
I removed hose clips from manifold water lines yesterday to compare water flow through each of them and noted that water appeared to gush for 2/3sec then stop for 2/3sec then gush again in this sequence. Is this normal or should i have a continuous flow of water?
Would anyone have any advice on where to chase the problem to from here?? Any ideas welcome
Thanks"
 
What do the T'stat hsg. wa

What do the T'stat hsg. water outlets where the hoses connect look like? Water should be a continuous flow. Hsg. may have a blockage. Are you sure the water inlet hose to the T'stat from the OD is putting out sufficient water? W/the water gushing it can't cool enough.
 
"Ian

I have a Maxum 2400 SC


"Ian

I have a Maxum 2400 SCR 5.0. Overheaded this summer and cracked "BOTH" heads. Did replacement myself and starboard riser gets really hot while port is luke warm at best. I know most say one will be hotter but I can only hold my hand on riser 10 seconds or less. I replaced T-stat, both hoses to exhaust, new cir pump, and impeller, but STD still gets hot. The alarm does not go off but the boat is in yard. Took it out last week and ran it the river for a mile and Temp went to 180-185. I put my hand on port riser luke warm and STD 3 sec only, it was too hot. Last night I restricted water flow in the port hose with vice grips just enough to decrease water flow to port and within 2 min STD side was luke warm and port very warm-not as hot as STD was getting but BIG DIFFEWRENCE, I could still touch no problem but significant difference in temps. I'm installing a valve on port side today and play with water flow until both even out in temp. I know it sounds crazy but I have replaced everything that deals with water flow. I even change flapper on that side!

hope this helps."
 
water should be gushing contin

water should be gushing continous. I opened both drain valve on both port and STD and water was gushing out both. Try to restrict water-don't completely block water passage just reduce it to port and see what happens
 
"...both the impeller and

"...both the impeller and water pump appear to be in good condition"

Change the impeller anyway.
 
"[i]When running, starboard si

"When running, starboard side appears to over heat

on the trailer?

normal."
 
"Same here

Just stop by Mar


"Same here

Just stop by Marine shop and sales person though of something. verse me cutting this $49 dollar hose I just pickeup up, why not use the four hole riser gasket on STD side and ristrictor gasket (2 hole) on port. It only took a little bit of restriction last night to chnage the temp of the riser. If the odd riser gaskets don't do the trick I will breakdown and cut the hose and insert a flow restrion valve

good luck"
 
"Just installed the two hole r

"Just installed the two hole riser gasket on port and 4 hole gasket on STD. I'll be dam if the riser just gets luke warm now
lol.gif
The true test will come tomorrow when i take it out to the river, but so far the restricted gasket seems to be holding up. The last resort would have been is to cut the hose and insert a flow valve and play with water flow untill each riser equals out. This comes after repalcing tem, hoses, two sets of riser gaskets, rotating risers, new impleller, and flapper valve. I really hope you solve your problem. I'll let everyone know how the river test goes this weekend. The STD riser got luke warm after 20 plus minutes :)

regards"
 
"took the boat out today for a

"took the boat out today for a test run. ran about 7 miles up river. the temp stayed at 175-178, could put my hand on port riser luke warm. STD riser maybe 12-15 max still too hot if you ask me. I plan to have an authorized dealer check it this week. I have replaced everything I know to replace. bot ran very well, stopped a few times to check and temp stayed constant at 173-178. I'll keep every posted"
 
"Zeke/All,
We took mechanic o


"Zeke/All,
We took mechanic out for a spin on ours at the weekend and ran the boat as hard as it would go for about an hour. he had his infra-red thermometer with him and recorded that starboard was running about 20deg (thats in celcius so not sure what that is in Fahrenheit)hotter. He didnt appear too concerned about the temp difference and gave us the old line that "one will always run hotter than the other" I like the idea of restricting the flow to port side a little to balanced them out.Will give that a go.
We also ran into a new issue when we were out on test run! We started to loose power after about 45mins. we could only build up to approx 3500RPM. Mechanic reckoned we had a fuel starvation issue. going to replace fuel filters, clean carburetor and air filter and bring her for another spin. then maybe look at fuel pump if that doesnt work. Also going to replace throttle cable as its on its last legs (7yr old)
Would appreciate you letting us know how you get on with your issue
Good luck!"
 
"Stop by yesterday and ordered

"Stop by yesterday and ordered a new impeller kit to install. While there I spoke to what many in the area call the Mercruiser experts of Hampton Roads. I asked the shop can the Them housing have hot water out on STD side and luke warm on port and both said yes! I then asked was 170-178 normal temp for merc 5.0 and both said that was about right. They asked if my alarm was working and did it sound. I said no. They said volve penta run hotter than that! After replacing two heads, cir pump risers, manifold, bellows, exhause and gear housing bellow, STD and port riser hoses I don't want to take any chances. I never really looked at the temp prior to the over heating issue. Although I was thinking it never went past 175! I'm going to do a water flow test this weekend before I replace the impeller, since i had a mechanic repalce this summer thinking that was my overheating issue. That just baffles me that I can lay my hand on that port riser for as long as I like and only 10 seconds maybe on the STD after running up river for 30 minutes or so. But the temp got to 175-178 and never got any higher on a 45 min run at 2500-3000 RPMs.

I would stop the boat every 15 or 20 min of running 2500-3000 rpms and feel the risers, and that's when I noticed one hose was pretty warm and the port luke warm.

I'll keep everyone posted on the flow test Saturday. I will do that before replacing the impeller kit and pick-up hose. Really don't want to tear my stern off again "lol" that was a bear by myself and first time!"
 
Any update on this problem. I am having the same issue with my 5.0 merc after a mani riser change. I changed the hoses and the t-stat and I am still having the same issue.
 
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