Strange Overheat Help Please!!

[ffemt3992]

1997 Yamaha 175 Saltwater Series 2 (Carb)

Motor ran great all year. I winterized it (ran rv antifreeze, fogged, stabil in tank) then wife decided we did it too soon and needed to striper fish. Pulled it from storage, ran great again, then after 10 min of *****ing in gear it overheats. Ran fine 30 min back to the dock.

On a hose at idle the starboard side is hitting 180+ and tripping alarm, while the port side is staying around 120. I've done a new water pump/impeller, new thermostats, checked popit valve, checked intake grates, even pulled water jacket and head cover to check for blockages and found none. What could cause one side to overheat like this and not other.

I'm stumped, frustrated and running out of money!

Please help!!!

[pstephens46]

What was the antifreeze for? How did you apply to engine? Outboards drain when you turn them off, should be no water left to freeze.

[boscoe99]

What was the antifreeze for? How did you apply to engine? Outboards drain when you turn them off, should be no water left to freeze.

Antifreeze is like using the choke switch on an EFI model motor. If it makes the user feel better then do it.

[99yam40]

the main word is should drain.

does not mean they will if there is some blockage in the wrong place.

OP I would think there is some blockage some where that is not allowing sufficient water flow getting to that side or pump is not pumping enough water. Did you inspect the housing when you redid the water pump?

Look up Rydlyme Marine descaler maybe if there is a lot of build up of scale

also, if an anode breaks loose and lodges in the wrong place they can cause circulation problems

[ffemt3992]

I've heard back n forth about antifreeze on outboards online, stories of cracked pockets or water jackets so I figured for $5 in antifreeze it wouldn't hurt and pumped it up through the muffs. local marinas here do the same w outboards as well.

the pump housing was good, no issues there, impeller was still somewhat ok but redid anyway. it seems there's plenty of water going up for the port side, decent stream flowing out as usual, popit valve ok (even shaved it a tiny bit at suggestion of local shop bc it was sticking a little at first)...

just running out of user-accessible places to check....

[99yam40]

just re read you 1st post and it overheated at low RPM but ran good at high.
I would have another look at the PRV and make sure there is not corrosion building up under the grommet causing the PRV to stick open sometimes.
They have a new style of plunger on some motors the help keep that from happening.
when you pull the grommet do not loose it into the motor

[ffemt3992]

Fixed... I remembered seeing online somewhere that the intake screens on these outboards were directional and often quite restrictive sometimes needing to be drilled out. I pulled them off completely and it ran on muffs for an hour at least no issues, strong stream... put them back on, stream pressure dropped in half! I'm not sure maybe because I have slightly lower pressure on my garden hose at home and new pump needed more water.. not sure (first time flushing here) but seems good now.. have to test in water to be sure.

[99yam40]

you drill the screen already?

[ffemt3992]

No haven't done anything with it yet.. was just thrilled it ran fine..