Engine Power

[Old Forum]

Julian Swindell
Username: Julian_swindell

Registered: 03-2007
   
Posted on Monday, August 24, 2009 - 09:52 am:      
So far I am very pleased with the Tohatsu. This whole outboard business is very odd. The Mariner and Mercury 4/5/6 engines cost £200 more than the Tohatsu, but they are all the same engines. All made by Tohatsu but rebadged and then overcharged for the new name. The three different power engines all have exactly the same specifications, apart from the power so what is the actual difference between them?

[Old Forum]

David Cawston
Username: David_cawston

Registered: 03-2007
   
Posted on Monday, August 24, 2009 - 09:00 pm:      
In the good old days of 2 strokes, the power difference between the Mercury 4 and 5 was purely different carb spec. Not sure if it was a different carb or just different jets etc.

[Old Forum]

David_owens
Username: David_owens

Registered: 04-2010
   
Posted on Tuesday, July 20, 2010 - 09:38 pm:      
I bought an external fuel tank with my recent engine and it fitted conveniently in my port locker. One had been there before, as there is a strap to hold the engine, and a neat hole facing forward from the locker into the cockpit, which takes the fuel line. However, after conversations in SeaFairhaven, reinforced by posts above, I realise this is not enough. I know others have sealed the bottom of the locker, so, how is this done - Martin's pic maybe? Also does one need to seal from the quarter berth that adjoins it? Does one really need to line with steel? And as my reading of the BSS regulations is that "the locker must not open into any engine, battery or electrical equipment space", does ventilating into the engine well comply with BSS? And, has anyone achieved full compliance with the BSS - which also specifies that the locker should be "drained to the outside" and self-draining?

[Old Forum]

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Wednesday, July 21, 2010 - 01:27 pm:      
I don't think a photo will show very much, but what I did was sealed the lower portion of the locker with foam and fitted a timber 'floor' on top of the foam. I used tongued and grooved boarding for the floor as it is impossible to get a single peice of ply through the top.Then I fibreglassed over the timber floor and the locker walls so that my vent hole (into the engine well) was at the locker floor level but not below water level! I also have a vent hole at the top through which the fuel line passes.
The locker is thus sealed off and petrol vapour and any escaping gas (I keep my gas bottles in here too)exhausts to outside. I have taken the view - rightly or wrongly - that although theoretically gas/petrol vapour escaping from the locker into the engine well cannot escape downwards from here, there is enough air movement to disperse it. I have also taken the view that my petrol tank which sits in a washing up bowl ('bund tank') in the locker is portable and therefore the locker doesn't have to be lined with steel. I suspect the above doesn't comply with BSS, but I am a great believer in 'the best is the enemy of the good' and I would never get around to achieving the 'best'.

[Old Forum]

David Cawston
Username: David_cawston

Registered: 03-2007
   
Posted on Thursday, July 22, 2010 - 12:32 pm:      
I have designed (but not yet completed) an aluminium drop in metal box with lips that hang on the locker opening and has a drain tube fixed on the bottom that will exit the transom through a fitting similar to the bilge pump outlet. This will comply with BSS regulations and will hold 2 x 5 litre petrol cans + small gas canisters. It is designed so it can easily be lifted out to access the space lower in the locker (the box has a maximum depth of 16"). All I have to do now is make a proper wooden full size mock up and take it to an aluminium fabricator for a bit of TIG welding. This will work fine on Markie as I have the integral tank on the motor, might not be suitable for separate fuel tanks as used on more powerful motors (5HP +).

[Old Forum]

David_owens
Username: David_owens

Registered: 04-2010
   
Posted on Thursday, August 12, 2010 - 06:12 pm:      
Blimey - that aluminium drop in box sounds impressive! I'll think on about this, as though I agree entirely with Martin about the best being the enemy of the good, I gather to get a BSS, it does have to be the best. If I get definitive information, I'll post it here. David, if you produce the box, would you let us know please.
While talking rear lockers, I've gathered after looking down them that they are connected both in front of, and behind, the engine well. I presume the bilge exits at the bottom also? Or are the bilges sealed except via the hose of the bilge pump?