Mariner 3.3 water flow

SpottyDog5

SpottyDog5

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I have just acquired a Mariner 3.3 LS, there is only the slightest dribble of water coming from the tell,tell. Its has recently had a new impeller fitted, so I suspect the water blockage is in the powerhead/water jacket. The question I have is do I need to remove the leg first or can I get to everything from the top? Thanks in advance.
 
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Common problem with salt crystals blocking the water outlet hole. A good way to clear the water way is to blast of air from a air compressor in to the water outlet hole it works for me.
 
SpottyDog5 said:
I have just acquired a Mariner 3.3 LS, there is only the slightest dribble of water coming from the tell,tell. Its has recently had a new impeller fitted, so I suspect the water blockage is in the powerhead/water jacket. The question I have is do I need to remove the leg first or can I get to everything from the top? Thanks in advance.
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Firstly have you checked the pee pipe and the connection at the engine end for blockages.

Very possibly blockages in the channels between powerhead and leg

Lakesailor's picture shows:

powwerheadgasketflange.jpg


a blast of air in via the telltale is unlikely to clear this

or possibly in the power head

gasketremoved.jpg



It is a rebadged Tohatsu and you will find a 'shop manual and more pictures on Lakesailor's site

http://www.lakelandimages.co.uk/Forum pics/info_engine/Tohatsu/
 
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SpottyDog5 said:
gordmac, I've got no idea.
Thanks Jamie, I've got a compressor,got to to be worth a go, cheers.
Click to expand...

That might work,if not you have to remove the leg from thr top,were it meets the power head. Six bolts if my memory serves me right. The blockage will be in the waterways on top of the leg.No need to remove the gear box.As long as the bolts come out a simple job ,half hour and a 10mm socket and job done.Good luck !


Sorry VsC beat me to it.Try the leg first ,it's usually the prob.
 
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I had a blockage in an outboard that had a new impeller. Some fool had used too much sealant and blocked the waterways. Since the outboard was attached to the boat on it's mooring and the garden shed where any work was done was a mile up the road, said fool was adequately punished, I feel.
 
Roy, buy 5 litres of rydelime from RK and run the engine in a bucket with it mixed 50/50 with fresh water this will circulate it and unblock the corroded waterways.
 
Thanks for the advice guys,
Quick update, the powerhead does come off by removing the six bolts attaching it to the leg, the internal water pipe feeds though 90 decrees into the water galleries, so no upper grommet to get blocked.
I think I now see the issue.....
20150119_184144_zpsyia1uh2r.jpg
20150119_182317_zpsmz5pu701.jpg
 
That looks pretty blocked. Before putting it back together spray the waterways with zinc chromate, it apparently is resistant to deposits forming so helps prevent this sort of blockage in the future. I was told this by a marine engineer, so I guess there must be some truth in it, and for a about a tenner, the spray can will outlast me!
 
For future reference this problem is an everyday occurrence in the cruising world I inhabit. The small Tohatsus and rebadged variants hang out in many lockers and rail mounts waiting as backups to the big OB used on the RIB.

I would not recommend dismantling the powerhead except as an absolute last resort. On an older engine this often results in stripped threads or broken bolts.

If the engine runs with a flow of water through it even if the pee hole is not peeing then run it. [Tilt the engine slightly with it running to see if there is water coming out with the exhaust.]

Poke a piece of wire up the peehole. This can be done without removing the flexible hose. There is a pretty good chance in my experience that this will start some flow. Just keep running the engine and poke from time to time and usually full flow returns.

The problem is not a hard scale but a soft corrosion scale that forms while the engine is not used. I am afraid that not many cruisers go to the trouble of a fresh water flush before storing the egg beater.

Of course if you do have a hard scale internal blockage then that prevents circulation and results in overheating then you have little option but in my experience this is rare.
 
Just taking off the cylinder head on a 3.3 is pretty straightforward, and if you slightly lubricate the bolts, it's easier to clear it out every 3 or 4 years if needed. The 4/5 seems less prone to silting up, probably because the passages are just a bit bigger.
 
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