Starboard manifold&riser hot / ,Port side is cold

[milkyway]

I have an mercruiser alpha 220hp with raw water cooling system.. On periodic engine idling while boat is on trailer, with fresh water hose plug for cooling, the starboard riser and manifold are so hot but the port side is cold. Thermostat reads 175 degrees. Feeling the water coming out of the drive, starboard water is very hot. Port side is cold. I don't know if this is relevant, but there's a lot more exhaust smoke ( or fumes) coming out of starboard side. Almost nothing in port. Briefly, what are the possible causes of this discrepancy in temperature? Thanks.

 

[rodbolt]

Re: Starboard manifold&riser hot / ,Port side is cold

most likely a clogged riser or manifold. they dont last forever. we normmaly find here a riser is junk in about 3 years.<br /> good luck and keep posting

 

[crazy charlie]

Re: Starboard manifold&riser hot / ,Port side is cold

Take it off and have a look for yourself.You may be able to clean it out but if you are able to dont expect it to last too long after.Maybe a year or two before it fails.Since you will have to take it off to check it you may as well replace it.Charlie

 

[Elk Chaser]

Re: Starboard manifold&riser hot / ,Port side is cold

Have you checked the spark plugs and the valves on that side? If you have a problem with the valves or plugs it is possible that they are allowing raw fuel into the exhaust and it is igniting there. <br /><br />That should also cause more fumes and smoke as well as higher temperatures on one side versus the other.<br /><br />Something to check if the manifold and riser are looking good.

 

[milkyway]

Re: Starboard manifold&riser hot / ,Port side is cold

I will certainly check the manifold and riser. Any website that has guidelines on how this is done? Have never done this before. <br /><br />Chaser, what should I expect to see on the plugs and valves if this is contributing to the heat? And which valves are you referring to?

 

[sealyons]

Re: Starboard manifold&riser hot / ,Port side is cold

I would definately check the manifolds and risers on both sides. If one side is plugged up the other will follow shortly if they are both the same age.

 

[crazy charlie]

Re: Starboard manifold&riser hot / ,Port side is cold

Milkyway,you have some good advise here.The Elk chasers suggestion is the last thing I would be concerned with because the chances of that actually happening are as slim as winning lotto.Sorry to dump on you EC but it looks like Milkyway was headed there while he should be removing and checking and or replacing the riser and or manifold.Charlie

 

[cc lancer]

Re: Starboard manifold&riser hot / ,Port side is cold

water coming out of the drive, starboard water is very hot. Port side is cold. I don't know if this is relevant, but there's a lot more exhaust smoke ( or fumes) coming out of starboard side.<br />Is it black or white, if white it could be steam, have you checked your manifold when the boat is in the water.<br />Since you are operating in salt water, some thing may be stopped up, or the manifold has died.<br />If possible always flush with fresh water, when you come in after boating.<br />Start at the thermostat housing take the line loose, you should see a white "ball", make sure it is free, they will hang, only allowing a small amount of water flow to the manifold, continue to the exhaust manifold, take the line loose, see how much crud has built up at the opening.<br />Then as elk chaser stated check the plugs, if one looks very different from the others, the manifold may be cracked allowing water into the combustion chamber. Good luck!!!

 

[milkyway]

Re: Starboard manifold&riser hot / ,Port side is cold

lancer,<br /><br />smoke is close to white - so it must be steam but I will check again tonight. Does the actual exhaust smoke come out thru the prop's area or also where the water comes out?<br /><br />Can you elaborate on the " manifold has died"? Is there safety concerns here and I should not boat until I get this investigated? Waht is the worst scenario? Overheat?<br /><br />How do I go about checking the manifold on the water? I always flush with fresh water after boating on salt water. <br /><br />What i have observed is that the hose about within 4 inches of the thermostat is soft when you squeeze it while the rest of the hose feels like it has some "UNEVEN" reinforcement inside.<br /><br />Thanks in advance.

 

[cc lancer]

Re: Starboard manifold&riser hot / ,Port side is cold

Milkyway:<br />My 260 merc. runs "hotter" on one side when it is on the muff, can't remember which side.<br />That why I said to check it out with the boat in the water. And I don't like to idle to long on the muff, just long enough to flush the salt water.<br />Start at the thermostat housing, you may have found the problem, the hose should feel about the same on both side of the housing.<br />Checking the thermostat outlets, making sure they are free is pretty simple. I had some heating issues, with my boat last year and one of the balls was hung.<br />If you have the boat in the water, idle it up to about 1-k, let it sit until the thermostat opens 175 degrees, then check the manifolds. If it is still hot on the star side, the manifold may be cracked inside. But first make sure everything is clean and clear.

 

[milkyway]

Re: Starboard manifold&riser hot / ,Port side is cold

lancer,<br /><br />got ya. thanks.

 

[steve n carol]

Re: Starboard manifold&riser hot / ,Port side is cold

on my merc 225s, 302 ci, one side runs hotter until the T-stat is FULLY opened...sl<br />Mr. lancer, I am not familiar with the "white ball" in which you are reffering too. What is this?

 

[Scaaty]

Re: Starboard manifold&riser hot / ,Port side is cold

My take is its steam, and your manifolds and risers are junk and need to be replaced. How many years in saltwater? If you get saltwater in that block you will be buying a whole new motor. Only a few years in salt can rust a exhaust manifold out from the inside. Sounds like you have water and hot exhaust gas mixing...no good. Check your oil. Is it milky brown? If it is, well, bad news. When you post, put the year of the boat/motor.

 

[milkyway]

Re: Starboard manifold&riser hot / ,Port side is cold

Please refer to my post " WHAT ITHE FUNCTION OF THE MANIFOLD". I have remove the manifold and elbow and I saw no problem.