Boater Sam

Wow! That looks good, you did a really fast job there, stripped and repainted in one day. Aside, was it your catamaran I saw in the Philippines of the west side of Negros? Sam.

Sorry to wee on your parade bigcol but that is probably a sensible thing to do. Even of you got that engine low enough you would never get under it to do an oil change. Was I right about it being an in line gearbox not a drop? Sam.

Looking at that number its not a dropped box but inline, there is the problem. See if PRM can change it to a 260D2.1, or sell it and buy anew 280D2.1 for around £1400. It may be cheaper and better solution than all the messing about and welding.

I've hired stripper for much less. What's getting stripped?

With a Python or Aquadrive you will have to have a thrust plate welded into the hull and on that wide stern of yours its not so simple as on a narrow boat. Have you priced the Aquadrive, thrust plate and new engine mountings as against altering the engine brackets and a Centaflex or similar in line coupling? Aquadrive for a Beta 90 will be expensive.

Unusual, check what the g box ratio is ?

I should hope that there is! This must be a very shallow draught hull with a tiny prop. A thought, that PRM box is a"D" something meaning "drop"is it not? What is the type number on the label? Like 160D2 or 260D2?

Remove the 4 brackets from the engine they are bolted on. Carve the tops of the brackets. Build up the brackets by welding steel on 3 sides by as much as you need to drop the engine to get it in line and weld the tops back on. Can all be done off the boat at a welders once you have measured how much drop you want. Are you certain that the engine will fit down in between the engine beds?

Fluff/debris in the air inlet venturi where the gas jet is.

I have seen an Aquadrive running at that amount of displacement but cannot advise it, they are designed to run slightly misaligned, not at a big angle. It should not be a massive job to lower the engine, an hour with a gas axe and a welder would see it done. There is no photo of the engine mountings so its impossible to say if it would be easy or not. The PRM gearbox is a dropbox already.

Classic blocked vent syndrome, its getting a vacuum in the tank as you use water. And pressurising as you fill. Leave one of the fillers loose, if the problem stops then that proves it. I would guess that the vent is connected to the tank top by a hose which has kinked or collapsed. Try inserting a length of say 10mm nylon /plastic pipe down the vent for a couple of feet, if you can get it through it will act as a vent inside the existing hose.

I'm curious as to why Isuzu, the largest diesel engine makers in the world, have stopped supplying marine engines for canal boats. They sound a little harsh to me, I can tell when an old Canaltime boat is approaching easily!

Used to be Haylon but I suppose that is banned now with the ozone layer depletion.

You need to measure the shaft diameter, accurately, not the outside. Do you have a caliper gauge? If not do you have a big adjustable spanner to use as a measure against a ruler? As a last resort, remove the bearing inner and measure it then.

Bearing supplier but I buy on ebay. You need to know the diameter of the rudder shaft, it can be either metric or imperial size. There will be allen grub screws in the bearing inner ring onto the shaft. You can buy just the bearing insert to fit in the 4 bolt casting but its easier to chuck the whole thing.