Overheating starboard side of engine

[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.

[Carl]

Ferm,

I retorqued the bolts about a week after I reinstalled the head. I have not rechecked them after I ran it yesterday. I will do that soon. I looked at the water tube for as far as I could see it when I had the lower unit off. This is what I had done when the lower unit off, the t-stats and the poppet valve out, I also removed the plug on the top of the engine and plugged all the holes and filled the engine with water to see where it would come out. It came out the t-stat holes on each side and then I pulled all the plugs and water flowed really steady until the engine drained. i can recheck the tube also. I think you mean the copper tube that is part of the engine and not the plastic extension that comes with a water pump kit. When I was trimming the engine, it never came out the water to disrupt the flow, but it was interesnting as to how it affected the flow. Do you think it could be related to something between the inlet holes of the lower unit and the inlet to the water pump. Would it be worth pulling the water pump housing and seals? Another thought - there is a short hose that is attached to top part on the forward end of the lower unit - I guess it is for speed indication. My previous motor had this hole plugged. Could I be loosing water out that open ended tube that should be going to the engine?



Thanks


Carl

[spareparts]

put a water pressure gauge on it and report back. When you replaced the water pump, what brand did you use? Did your replace just the impeller or did you replace the housing as well

[Carl]

I used the Mercury OEM pump kit replacement included Impeller, gaskets, upper housing, small plastic water tube etc. For the pressure gage, does this get attached at the hole at the top of the engine that has a threaded plug in it?

Thanks

Carl

[Carl]

I think I may have found my issue with the water flow on this engine. I was running at 3K rpm and inspecting the engine for any source of water leakage where it shouldn't be. I found water spurting out at the exhaust plate connection - where the power head meets the exhaust tower. It looks like a piece of the gasket is compromised. The higher the rpm, the more water spurts out this spot. Does this sound like the culprit? How hard is to to replace this gasket? I'm assuming the power head has to be lifted?? Annything else I should replace if I separate the powerhead?

Thanks

Carl

[spareparts]

I think you just found it, the exhaust pressure will get into the cooling passages and prevent water from entering(exhaust pressure greater than water pressure), you will have to pull the power head. The power head bolts(studs) can be a pain