Finnmaster 6100 MC

Hi Trevor,

Don't worry too much, as mine does the same, the reason being that the GRP sunroof doesn't have any seals around the edges. Therefore, to overcome this, when washing down, I always ensure that I do not spray the water up underneath the sunroof, but just let the water flow off the roof, which stops any water entering the cabin.

To date, I haven't found a way to successfully seal the roof, but at least I have never had any rain water enter through this roof gap.

One other downside to this design is that, in colder weather, I do get draughts through the sunroof gap. :apologetic:

Cheers, Allan
 
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I am getting water into my engine a Mercury 150 Optimax V6 and am at a loss? It must be getting into the on-board built in fuel tank but no sign of fuel in the bilge below. I have checked the fuel filler and am looking at the fuel vent on side. It has been suggested that the fuel tanks on the older Finnmaster 61 CA corrode at the bottom because the bottom of the boat is not flat but arched and salt water can gather and cause this problem. My mechanic is to pressure test the tank for leaks. I have had to replace 3 corroded air injectors and all pumps . Any suggestions please. Trevor. Campbell4@btinternet. Com
 
Hi Trevor,

Sorry to hear of your troubles, however, I'm surprised your Mercury hasn't got a fuel water filter fitted, as my Honda 135 has one of these to protect it against water in the petrol.

My 61CA has an aluminium fuel tank and, as my bilge is completely dry, I hope the possibility of the tank corroding is very limited.

One thing to check is the fuel filler O-ring as this is prone to cracking, and can cause water to leak into the tank.

Hope you find the source of the water ingress.
 
Allan. Thank you for the interest. The water separator on the engine was full of water. I have asked the Mercury engineer to check the fuel filler cap O ring and he commented that even with no O ring at all it would never get this amount of water in. He is exploring the wash on the side of the boat getting into the fuel tank breather when there is too much bow down with the engine not trimmed out enough? I feel he is going to move the breather to the rear of the boat where there is no wash. Will update the thread when all is revealed - if ever. Cheers. Trevor.
 
The breather on my boat exits on the port side of the transom where it curves inboard, where there is no chance of any wash ingress, so your proposal to move yours aft would be a good plan.

If you have such a large quantity of water in your tank to fill the engine water separator, I agree that it's very unlikely the filler cap is the source.

Let us know the end result...good luck!
 
The more I read on forums about Mercury optimax engines the more I fear. They appear over engineered now and are giving trouble from all directions. The oil feed from the large onboard tank to tank under the cowel seems problematic with loosening caps to faulty sensors causing endless beeping and computer messages. The 150 Opti I have has been guilty of all of this. Is the any chance of getting a season after professional service with Mercury mechanic that I could get a few months without having to continually take boat out of water and tow 80 miles round trip to the Mercury workshop? Not enjoying my Mercury at this time.
 
Spoke to my Mercury professional today and he is convinced the water has entered the fuel tank via the fuel breather from the bow down wash as there was sea water in the tube going from breather to tank. Should have been a loop in the tube to prevent this. He has moved the breather to the rear of the boat to avoid wash. Will know soon when back on water. This little water incursion has resulted in 3 injectors being replaced and the two fuel pumps may also need replacing. More ££££££.
 
Hopefully, this was the source of the water, Trevor, and hope you don't need new fuel pumps.

When I was at my boat over the weekend, I checked the route of my tank vent, and I was mistaken, as it exits on the starboard side of the hull, in line with the cabin aft bulkhead and, whilst I haven't experienced any water ingress into my tank, I might investigate adding a deflector to the hull fitting.
 
Probably a good idea Allan as a stainless steel clamshell will cost about £10 and as I have said water damage is expensive. Have a good season. Trevor.
 
Boat back in water and had a good run around today up to 40 knots at times with no obvious problems. The break down must have been water getting in through the breather which has been moved now. Hopefully that will be the last of large bills this year as the engine has only got 70 hours on it. More sun please.
 
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