What is if a 3 HP Malta not always sends water out of the pee hole

[iveasmalta]

Simple anwser:

When the impleller is new/operating well the water will come out of the pee hole like a strong jet. As soon as the thermostate opens the jet is still nice but a little weaker. Check it out!

When the impeller lifetime is almost over or rahter the whear on the rubber is starting to get to big, following occures:
As long as the motor is cold and the thermostate is closed, the pressure is high enough to let water comming out of the pee hole, but only a little water will enter the hot area of the exhaust , 1/3 upper cyliner and head. This little of water will suddenly start to boil to a steam. this steam-pressure will force against the weak feeded water comming from the impeller. As soon as the steam force is higher than the impeller pressure, the water flow through the pee hole stops. Due to that the pee hole has 2mm in diameter only, we can not see any steam comming out of it. The visible steam will leave to several other channels/shortcuts. But you can feel the small , hot backpressure if holding the pee hole closed with one finger.

 

[anoccasionalyachtsman]

Unless you know that it's had a major overhaul and always flushed after use I'd bet on the head and cylinder channels being badly blocked. I've had three of these and was quite surprised that two of them were still usable because they were completely clogged.

That said, I'd be surprised if the pee hole chamber was blocked - it shouldn't really get hot enough to dry the salt out - so maybe there's a problem down in the inlet or the leg pipe. Either way, I'd be be taking the leg off for a look. Good luck with the screws! Don't try and undo them completely, undo a few degrees and retighten, repeat until you're confident that they're actually turning and not just twisting.

This was the worst of the blocked ones, and you can see why I was surprised that it was so bad. That's the pee hole chamber on the right.

 

[iveasmalta]

I do see you pic on the message email only. Here in the forum it is not attached, No clue why...

But anyhow, I fully agree what you are saying! The pee hole can be blocked by larger particels sucked through the impeller pump, but the first chamber where the pee hole is will not get filled up completely. If you take off the upper shaft, take off the exhaust pipe as well. (You will need a new gasket for this too!) There is in my experience the most risky area for a Malta to get a restricted coolant flow. Later this evening i will try to make some pics. As promizes see attached photos. Smallest section are the 90° turn from inlet towards the exhaust cooling channel and from the 90 turn from this into the cylinder wall cooling section.

Other pic shows de depth of teh coolant channel and the relatively small width.




Do have 6 Malta and did cut the worst one (fully corroded) to see how much space for tuning the japanese did had left for my pleasure.

In addition to the screws. Replace them if unlocking was tough, even if they seem to be OK.

 

[anoccasionalyachtsman]