Hello Richard, only just read this post. I might be wrong but is the 4hp Mercury the same engine as the Mariner and Yamaha. There are often Mariner engines on ebay, often dismantled too, and lots of old Yamaha engines. If so you should be able t get hold of a knackered one. It seems likely that the shaft would outlive the powerhead. The spare parts seem to be extortionate considering that this is one of the most mass produced engines of all time and is widely used all over the world. Paul
Clint, there is loads of information about this on the internet, western towing have a good site. But it depends mostly on the suspension units fitted to your trailer. The rating should be stated on the chassis plate near the towing hitch. These units can be replaced with upgraded ones to provide a better ride. If this is done you should make sure the chassis plate is modified accordingly, which I suppose means it is better to have it done by a garage, although it would be a relatively easy DIY job (with the usual caveats). You can get your trailer weighed at a public weighbridge, but you may also find one at a quarry or local aggregates dealer.
Weighing in a bit late on this one. According to previous owner, Partan and trailer complete weigh around 1100kg. Trailer has been uprated to 1300kg and car can tow in excess of this, so plenty of margin for safety. Tows beautifully without any drama at all. You certainly don't want an unbraked trailer. I believe nose weight is an important factor, therefore weight distribution within the boat. Thus, heavy things I keep in the bow for sailing, go in the cockpit for towing.
As a further answer to the original question, we have just completed an 11 day cruise on Partan. 2 adults and 1 child slept on board every night, and we're still talking. The availability of showers and cooked meals on the Broads certainly made life easier. The boom tent that came with the boat has sadly worn out so we made do with a £3.99 tarp from Proper Job and some bungees. If any one knows how to weld/glue cheap plastic tarps I reckon I could make a new fitted tent for about a fiver.
Thanks for all the replies. They have a 10mm nut on the back, very difficult to get to, but I've got thin arms. Originally glassed in but now with a large washer to hold them proud of the strengthening pad. I shall replace with a piece of stainless stock, drilled and tapped to take the machine screws and long enough to hold from inside the locker. This will make them more accessible and they will lock against each other, preventing them from spinning. This mod has already been carried out on the lower one.
Help anyone please! I am removing the rudder pintles to paint the hull and so that I can give them a good polish, but how are they secured? I assumed a captive nut on the back, but having loosened them, they didn't screw out any further. I tried to tighten them back up again, but they just spin. Can I get to the back of them, and what will I find if I do? There seems to be a very narrow space between the transom and the inside of the engine well, but I don't fancy my chances of getting in there.
Partan has a paddle wheel log mounted in the starboard aft locker. It is packed around with black mastic and does not leak. As far as I can tell there is no foam here as it appears to simply fit through the hull. When heeled over on starboard tack it lifts out of the water and is rendered useless.
In addition to all the good advice already profferred, I just wanted to add that it's a good idea to avoid using the handbrake while the trailer is parked for long periods as everything has a tendency to seize up in the on position. Much better to use wheel chocks and save the brakes for manoeuvring and towing. Are you anywhere near Somerset, I'd be glad to assist and get acquainted.
Thanks for the prompt responses, I think I may try the US option while I tap away making replacements by hand. A word of caution about using gasket compound on carburettors though; even the tiniest fragment of Hylomar detaching itself in the float chamber or elsewhere could block a jet and cause the engine to stop and not start again till stripped down and cleaned. I would stick to gaskets lightly smeared with grease, which is why I want new ones which can still be compressed to make a good seal. If you have defects big enough to require a gap filling compound then your carb is probably junk anyway.
It would be interesting to find out if the same carb is used on any other engines like lawn mowers or generators, which might provide an alternative source of parts. The Lister/Petter diesel in my mate's boat is the same as used on truck refrigeration units and you can order parts direct from the manufacturer. By the way, a full engine service for a new Beta diesel in a 40 footer cost less than the quoted £85.
From the forum it would seem that many owners have replaced the original engine. Partan still has her original Mariner 4 (2 stroke) which is in very good condition, however, I would like to service the carburettor by replacing the gaskets. The best quote I have obtained was £85!!! for a few flimsy bits of paper. Given that this is one of the most mass produced engines of its type in the world I can't help thinking there should be a better deal than that somewhere. I was bracing myself to pay a fiver for them. Does anyone know who can supply these for a sensible price? I will make them if I have to, but they are a bit fiddly.