One manifold is hotter than the other...

On my 86 2001 I have noticed that one exhaust manifold is always hotter than the other one. Is this a sign that my circulation pump needs to be replaced?

I can hold my hand on one side, and the other side is too hot to hold my hand on. I checked the hose coming out of the thermostat housing and there is no blockage there.

Tim

When you winterize do you remove the rear drain plugs or just run A/F through the block from a bucket?

Hollywood-

I pull the plugs every year and run it to clean out the manifold. Once it is clean I run the anti freeze through it using the engine pump.

Nutty-

I did do exactly what you said, thought I had said that in my post.

Tim

I've had that problem when I Sh#@ an impeller. The little rubber pieces get stuck in the smaller hoses and block the water going into the manifold resulting in one a little warmer than the other.

Look at your plumbing of the raw water pump on how it supplies constant flow to cool the exhaust. Is the connection closer to one side? When the thermostat opens, the hot water is going to be pushed to one side more than the other.

DID ANYBODY CHANGE THE RISER GASKETS? IF THE GASKETS WERE PUT IN BACKWARDS THEY COULD CAUSE THE SAME PROBLEM.

JR_VIC -

I have the exact opposite on my PCM 351. Less water and hotter riser on portside. (my raw water pump is on starboard)

Are you sure your info is correct? (Not suggesting it's wrong...just researching some similar problems I'm having).

Thanks,
Sheri

JR_VIC wrote: I had the same issue on my 92 SNCB with a 351W. After I changed to Hi Teks I noticed that the starboard side is almost 40 degrees warmer than the port side. I called Ski DIM and they confirmed directly from PCM that the Starboard side will run hotter than the port side but I got no answer as to exactly how much hotter it will run. They backed this up because if you add the OJ Dripless shaft seal PCM and OJ recommend pulling water off to run to the shaft seal off the port side of the engine because there is more water flowing to that side than the starboard side. Again, I don't know how temp variation is acceptable but this information may help in knowing that some difference is normal. Thanks!

I pulled this old thread up tonight while searching for ideas on why my starboard side manifold has been running hot after a certain marine mechanic and inboard transmission specialist from Brunstucky replaced my manifolds which both had cracks in them, installed an OJ dripless seal, and rebuilt my trannny which was leaking pretty badly and was making clunking noises when put into gear.

While the transmission is now smooth as silk, the starboard manifold is getting really hot. So, I called this Brunstuckian, (who also stole one of my favorite shirts while in Green Lake, WI.) and asked him why the #$%& this was happening after he replaced the manifolds. He was puzzled as much as I was. I just took the RWP off and cleaned all the surfaces and put a new impeller, and gasket in even though the impeller was less than a year old and looked fine. I didn't see any air running through the strainer and I took the strainer apart to make sure it was clean.

So I was searching CCF tonight trying to find some clue to what is causing this and I came across this old thread. This part of JR VIC's post made the light bulb in my head go on.

"because if you add the OJ Dripless shaft seal PCM and OJ recommend pulling water to run to the shaft seal off the port side of the engine because there is more water flowing to that side than the starboard side."

Should the hose for the dripless seal tap into the hose that runs from the thermostat housing to the port side manifold instead of right after the RWP where the Brustuckian mechanic installed it?

I am going to go to Home Depot in the morning and pick up a 1" plastic coupler to attach the hoses together where the "T" for the OJ seal is now and try moving the water supply for the OJ seal to the hose before the port side manifold. This makes sense since the port side manifold seems to have plenty of water flow. This is only temporary, if this fixes the water flow I will replace the hoses.

I hope I have figured this out.

I moved the clear hose to the dripless seal from after the RWP to before the port side manifold and it didn't seem to make much of a difference. The starboard side is still a lot hotter than the port side. I didn't run it hard for very long since the weather started to turn bad, but I could keep my hand on the port side comfortably but the starboard side got hot enough to where I could still touch it but wouldn't want to leave my hand on it for very long.

The sound that Eric mentioned above went away after I loosened the belt on the RWP. I think the belt was too tight and that was what was causing the sound we heard.

I have no idea what is causing this.

Hey Tim, what did you do to fix this problem two years ago???

Harbor freight has a laser thermometer for $26.99. I could pick one up.

I think I may try removing the Perko flush unit and see if that may be restricting the water flow.

Randy, another thought, there really is not any guidelines on manifolds, old manifolds do get restricted and the water sticks around longer to transfer heat, on fresh clean manifolds the water is barely restricted and flys through these manifolds unabling them to transfer heat. temp readings will help to determine what is correct and what isnt, they are exhaust manifolds and typically are the hottest part of the engine, they are cast iron and the same as on cars and cars will see 700 degree temps. are we chasing our tail here?

I wasn't able to get a laser thermometer. I went to two different Harbor Freight stores and they were both sold out of them. Must be a good deal, I got a raincheck and they said they would call me when they come in.

I took the boat out last night but got out a little late to really run it hard. Your only aloud to run fast until 8pm. I took a couple laps and it seems the same with the Perko flush removed. I could leave my hand on the port side manifold all day but the starboard side I wouldn't want to leave my hand on for more than a few seconds. Running it at idle seems to cool the starboard side down to about the same temp as the port side after a half hour or so.

I did notice a little bit of air bubbles running through the clear line to the OJ seal now that it is on the hose going to the port side manifold. No air bubbles in the strainer cup. Maybe it is pulling some air through the pump?

Randy - I assume you have the intertaflow. It took two of us, but we were able to wiggle it enough to remove the muffler w/o removing the risers. Loosen the clamps well & use a screwdriver to break the seal of the hoses to the risers.

Hope it is your hose, you must be frustrated. Maybe you should just hacksaw thru the hose, sounds like it is bad anyway.

Let me check the '93 sport here before you tear anything apart.

I personally do not think you have a problem.