Overheating starboard side of engine

[Carl]

Thefermanator,

I replaced the soft parts of the poppit valve and ran the engine without t-stats just to see if they were creating the problem. It seems to be happening regardless.

Another crazy thought - could this be an oil issue? The previous merc I had did not have direct oil injection I just premixed. This engine had the oil pump and tank all connected so I left if assembled. Does the oil pump feed the engine between port and starboard or top middle and bottom through the carbs?

Thanks

[THEFERMANATOR]

The oil injection is fed through the fuel line before the carbs so all cylinders get the same fuel oil supply. Take the hoses off teh t-stat housings and see if water comes out of them with it running. You may have a plugged hose or a blockage somewhere inside the block.

[Carl]

Thanks for the info on the oil injection. I'll check the hoses too. Another question - If there is a blockage in the engine block, would I gain enough access by pulling the cylinder head, or would it require a more invasive disassebly?

Thanks again

[THEFERMANATOR]

Most problems with low flow can be traced back to a stuck open poppit valve, but if there is a blockage then yes the heads will have to come off. i've never heard of this kind of problem on the MERCS though.

[spareparts]

didn't randleman have an issue with his merc, before he went fourstroke? I think the cooling passages were packed full of sand

[Carl]

Alright - fast forward almost a month from the last issue. I rebuilt the water pump, replaced t-stats, replaced all the parts of the popit valve and pulled the head just to be sure there was no blockage - (there was not). So I put everything back together and tested it in the yard. Everything seems good. I put it in the water today and let it run at the dock - all seems good. Then - I am running around putting it through the paces and I notice the pee stream falls off and not soon after I get the beep of the overheat. I can quickly get the temp down, buy shifting to neutral and reving the engine over 2k rpm (poppit valve opens) the pee stream is really strong and engine cools right down. This goes on about every 10 minutes or so. I can affect the strength of the pee stream by playing with the tilt of the engine.

My question after all this is: Does this seem like a water pick up issue? The engine runs cool as long it is not moving in the water. Now another issue. - I have a 25" lower unit curruntly on my boat which calls for a 20" motor. I have it bolted as high as it can go, but it is still 2 - 2.5 inches too low. Could this be affecting the water pickup? Would a jack plate fix this issue?

Any ideas are appreciated. I have not done much boating and it is already the end of July.

Thanks


Carl

[THEFERMANATOR]

When you had the lower unit off, what did the water tube look like? I have seen a few of them with messed up water feed tubes that would do this. Also retorque all of your head bolts. The longer leg isn't helping you, but shouldn't cause it to lose water unless you are trimming it really high. I know that the V-4 lower unit is known for cavitation issues though as I lost my 140 twice on my 19 angler because it would sometimes quit peeing. Put it on a 19 foot bowrider and had no more problems with it. Make sure you don't have anything under the hull that could be causing it to cavitate like a water pickup or transducer.