My motor has a threaded hole to the right of the upper spark plug. Water shoots out of the hole while the engine is running. Does this take a plug or bolt(what size)?
If you cover it with your finger(be careful might be hot) does your engine pee from somewhere else? I think most mercs had an plug on the water jacket.Mine does,and every one ive seen does.There is a brass bolt that goes in it.
This threaded hole should be for your overheat sensor. The sensor measures the temp of the metal (it is not a thru hole to the water). If you are seeing water here you will need to replace your cylinder block cover gasket. And it must be leaking badly if its shooting out. Obviously the sensor has been removed at some point. What is your serial number?
The gasket you need is 27-65490-2. You may want to consider getting that temp sensor, although they are a bit pricey at about 85 bucks. Simple job to change out the gasket,torque from the center bolts outward. Mine were 70 inch pounds, check your manual for your specs.
BP,
I just replaced my water jacket gasket. My motor is an 89 35hp two cyl. two stroke. The only "threaded" hole I had in my Cover had a short brass bolt in it as Cell said. I took a pic of the cover before I took it off so I could be sure the wires were put back correctly. I took the pic with my daughters camera and had her e-mail it to me. I printed it and deleted it. It showed the brass bolt. If she still has it on her PC I'll post it tomorrow. My question would be, if it is the threaded hole that the brass bolt goes in what happened to the bolt?
Mike
True the overheat sensor does not thread into the cover.It threads into the block,just adjacent to the cover and just to the right of the #1 plug.You will note the cutout in the cover at the top cylinder to allow clearance for the sensor. Yes there is typically a port on the cover itself between #1 and #2 cylinders to utilize if one were to desire a water press gauge fitting. If not a simple pipe plug fitting is installed there. Hope this helps.
Well the sensor is only half of the warning system. You also need the horn,which would reside in the control box if you are remote. If a tiller not sure where they were mounted in those. Look for a terminal block on the right side of your motor about 5-6 inches fwd of where your plugs are,this is where the sensor ties into the main harness.Nice to have the warning system serviceable can save you big headaches later. Wire color would be tan for the overheat warning wiring.
You may not need either one. Go to this web page and check out part number 38. "Plug" $2.15 http://www.crowleymarine.com/mercury_parts/334/90.cfm That may be all you need. The other parts are there also, if you think you'll need them, but I'd put the plug in the motor first. I had a lot of water coming out from the cover at the the lower spark plug . The old gasket had blown out. the old gasket had oversized holes around the spark plugs. There wasn't much sealing area. The new gaskets are redesigned. Fit the way they should. Try the plug first. Unless you drop the lower cowl it's a pain in the butt to get to the bottom three bolts on that cover and dropping that cowl is a job from what I've been told. I didn't. Took me a while and the top bolts are torqued to 100 in lb. The bottom three I guessed at.
Mike
Disregard the other posts. That hole is for the pee. You should have a threaded elbow and on that would be a rubber hose that is routed down to a small hole in the base of your cowl. You should be able to pick up a suitable elbow at a Lowes or home depot.
BP You're sure getting a lot of advice. This is my last post. Pic below. This is what my water jacket cover looks like. You can see where the high heat sensor is. Right beside the upper spark plug. I'm pretty sure thats NOT what you're talking about. You can also see where my brass plug is. If your motor looks like mine and you DON'T have a brass plug where mine is........ if you just have an empty threaded hole, put a plug in it. Start your motor and see if you have any other leaks back there. If you're not leaking and have a stream of water coming out the pee hole (lower right side of motor looking from behind) go fishing. Thats where I'll be very soon. My motor is running (and peeing) just fine. Hopefully yours will be too. Service manual calls for red locktite on threads.
Mike
Adding my two cents - if it's not the temperature sensor (about 1/2" or so from top plug) then the brass plug shown in picture is for a water pressure to a gauge--that's what i use it for.. Hope this helps someone.--Have a go day..
Mercury 35hp hole next to spark plug?
Linear Mode
