First off, I just had the impeller replaced two weeks ago for the same problem, but I’m still having issues.
When I start the motor, it takes longer than normal to start peeing. Also, there is some, what appears to be, steam. Then it does just fine. When I get up on plane at WOT, or just under, water & steam start spraying out of the pee hole after a minute or two, instead of a steady stream. If I back off the throttle, it goes back to normal.
It started doing the same thing in April of last year, not too long after I bought the boat. Then, I changed the impeller myself, and all was well till now.
Other than that, the motor starts and runs like a champ.
I haven’t called the dealer back yet. I wanted to get some thoughts first.
Bob Van Gundy
Marine Designs,Inc.
Custom Aluminum Fabrication
803-727-4069
Ok, I went out & pulled my cowling off and looked for the thermostat. I couldn’t find anything that looked like it could be a thermostat housing. I found the hose that goes from the pee hole to a fitting on top of the motor. All other hoses were verified fuel. Do I need to remove the lower cowling?
Can anyone help me out?
Thanks, Bob
Bob Van Gundy
Marine Designs,Inc.
Custom Aluminum Fabrication
803-727-4069
I DONT HAVE ENOUGH EXPERIENCE WITH THAT PARTICULAR MOTOR TO TELL YOU WHERE THE STUFF IS WITHOUT LOOKING AT IT, BUT IN GENERAL, THE THERMOSTAT IS GOING TO BE AT TEH TOP OF THE HEAD, AND THE PRESSURE RELIEF OR POPPIT VALVE IS GOING TO BE AT TEH BOTTOM OF THE MOTOR
When you replaced the impeller did you replace the housing and/or wear plate? Could be that one or the other are damaged and taking out the impeller prematurely. I’m also not overly familiar with this exact motor but I’m just trying to provide some ideas.
Chris, I have yet to find anything that remotely resembles a thermostat housing or relief valve.But I’ll keep looking.
Tico Tiger, I’m beginning to think that I don’t have one, like the guy with the same year & hp. Mariner.
bmarvil, The housing was not changed, but wear plate was. At least he told me it was. I may end up doing it again myself & replace the whole assembly. I was just trying to save myself the hassle of pulling the lower unit.
Bob Van Gundy
Marine Designs,Inc.
Custom Aluminum Fabrication
803-727-4069
I had a '87 30hp Mariner and it had one. I had a Seloc manual. It’s only about the size of a nickel and near top of the head. Sounds like it’s stuck. 2x on doing the whole housing and plate. Best to get the kit and not just the impeller.
I’ve come to the conclusion that my motor has neither a thermostat or poppet valve. I’ve got at least 6 responses on 2 other sites that say no thermostat on that motor.
Here is the last one:
Today, 07:07 PM
Definitively no thermostat or poppet valve on that engine (the 44cu in 4 cylinder Mark 58-Merc 500- Merc 50 Classic 50 45hp and the Merc 40)
Perhaps the tube that goes from the lower unit to the engine is missing a rubber sleeve or is bent and not seated right.
Last edited by mixerjv; Today, 07:19 PM. </font id=“red”>
I’m going to go ahead & replace the complete water pump assembly kit myself. I’ll be checking that tube also. The mech. that replaced the impeller told me, after the fact, that the tube seemed a little loose. Why he didn’t check a little more is beyond me.
Bob Van Gundy
Marine Designs,Inc.
Custom Aluminum Fabrication
803-727-4069