Mercury 3.3 two stroke water flow

ianc1200

ianc1200

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I have a Mercury 3.3 two stroke (came with a motorboat I bought for it's tender) and am concerned re water flow. I have recently replaced the kill switch, then the impeller, and finally the gearbox oil. The flow when I put it back together (a complete afternoon getting the lower leg in....) was the same as before I took it apart. I've seen YouTube video's where there's a good volume coming from the head, others where there's only a drop or two, like mine. There is a good spitting action at the lower outlet. Is this normal or should I be worried? I've uploaded a short YouTube video to show this.

 
The head could be blocked with salt deposits. Its a common thing over time with these engines. Remove the head, its really easy as its 4 bolts and the head is only some 5-10mm thick. You will then see the water jacket full of crud. Rake it all out and reassemble.
 
Ive a Tohatsu, which I think is the same engine. Did a pump impeller change a couple of years back and ended-up with the same symptoms - virtually no water from the pee hose. It ended up a very simple fix..... once I found the small o-ring that seals the pump outlet onto the lift pipe to the engine head lying on the workshop floor! Before dismantling the head etc. make sure that the pump outlet has the o-ring seal where the pipe joins the pump.
 
ianc1200 said:
Did this yesterday - not blocked or any debris.

Looks like getting the head off needed.
Click to expand...
Not a job to be feared, as it's really very straightforward to do. As many others have had to, I surmised that the engine block was pretty much totally blocked on the Tohatsu 3.3 that I'd bought as 'scrap'. The head came off easily, and the block was easily cleaned with a long screwdriver, lots of water, and a bit of effort. It was then thoroughly dried and cleaned, given a magic spray of WD40, and reassembled. Once put back together, it started perfectly, and runs really well to this day.
One word of warning though, the head bolts might be seized, really be careful with those, but if one does break off, it's not the end of the world, as being a 2 stroke the head is OK with only 3 bolts in place! I lost patience with mine and told myself that I'd extract the bolt(stud maybe) if the engine didn't work. It did, and all seems fine with it still after maybe 50 hours of running. As you'll know, the piss pipe is piss poor, so I rigged up a better one with less of a sharp turn from the outlet; I ran the hose through the engine cover onto the outside, which has made it a lot less liable to clogging.
 
I didn't read this thread yesterday.... Two bolts came out OK, one snapped & the fourth isn't budging. Thinking
of putting back together and running in tank to get warmed up, then trying again.

"Ive a Tohatsu, which I think is the same engine. Did a pump impeller change a couple of years back and ended-up with the same symptoms - virtually no water from the pee hose. It ended up a very simple fix..... once I found the small o-ring that seals the pump outlet onto the lift pipe to the engine head lying on the workshop floor! Before dismantling the head etc. make sure that the pump outlet has the o-ring seal where the pipe joins the pump."

I think getting the leg off & (particularly) putting back together is easier than getting the head off.
 
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