Dolphin 12hp Marine Petrol Engine?

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Chrusty1

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Mayhap, I will be inheriting a Dolphin 12hp engine, it is the MK1?? with a somewhat idiosyncratic arrangement for altering the direction of travel, (stop the engine, then start it in reverse).....

Does anyone have any experience with these engines? I understand that the MK2 is a better beast all round it having a proper gearbox. I would be very interested to hear what the panel thinks, good things or bad. I have noted that the engines are still built in Cornwall, and that spares are no problem?

Smarty pants comments about getting a diesel engine instead wont be very helpful I'm afraid. /forums/images/graemlins/smile.gif
 
I had one in a Achilles and it was a reliable 2stroke, Having to stop the engine then switch to reverse was a bit daunting at first, but having said that it does focus the mind and make you think ahead! /forums/images/graemlins/grin.gif
 
I have had one for 6 years and it has been brilliant. It is reliable, smooth & powerful, there is no vibration and the sense is of having a small turbine under the cockpit. The stopping & starting in reverse is no bother as they nearly always start! seriously the only time they might not is if you have caned the batteries and flatted them. The prudent Dolphin owner always has a warp coiled up ready to lasso a bollard coming into a lock!
As for the mk 2 with gearbox several people in our club fitted these not trusting the direct reversing mk1. These proved to be nowhere near so reliable having electronic ignition problems.
The beauty of the mk 1 is its lack of weight & very compact size, It is quite possible to unbolt it & take it home for the winter. If you have a small boat & dont want or cant fit a diesel due to space or cost it is well worth considering a Dolphin.
I beleive they are no longer making new ones due to emissions regulations but reconditioned units are available as are spares.
They were also buying old ones in for rebuilding.
 
Had one in my first boat .It was a fantastic bit of kit and it never ever let me down.It was light easy on fuel and made so little noise that it reminded me of a sewing machine.The stopping and going into reverse was a bit of a problem as the controls were in the cabin and a bit of foresight was needed,If I had kept the boat I would have moved the control into a cockpit locker for handiness.
The servicing was apiece of cake no oil to change no oil filter made it a very clean and fast operation.Go for it.
 
I had one for 14 years on a Mystere in the 70s & 80s. For the most part it was brilliant, being lightweight and smooth-running. Some of the older plugs used to get fouled up but I changed to something better and had no trouble, as well as my getting better at running the engine harder and not idling for long. Once the engine is warm it restarts virtually on the first turn, so one soon gets used to the technique when approaching a stop of stopping the engine, restarting in idling reverse (when it is disconnected, via the centrifugal clutch) and giving a sharp burst of throttle to stop the boat dead. Very satisfying, though very disconcerting to anyone else nearby.

With an inflammable fuel involved you need to make sure the arrangements for ventilation and fire-extinguishing are up to the mark.

I recall that we occasionally had problems with our small batteries and 8 (or was it 12)amp dynastart when we'd been stuck in harbour, but I got quite good at hand-starting, which required one to wrap a line round the clutch-plate at the rear of the engine. I never had a problem with the complex electrics.
 
Many thanks to all that replied, it seems that it's pretty much all good then.

Cheers all. /forums/images/graemlins/smile.gif
 
Agree with everything said, I've never used any boat with such a smooth engine.

It being a two stroke you really need to keep it de-coked, plugs immaculate, and a reliable starter only battery. Ignition timing (points) needs to be spot on, and a new coil is cheap.

I'm not scared by petrol boat engines (same as the Americans). I would look at fire security - upgrade fuel line, arrange a compartment blower to run before start, and make sure that fuel leaks are contained within the blown area.

There used to be a material known as 'explosafe', which was, in reality, Aluminium swarf, which when rammed into a tank, occupied 1% volume, and stopped any chance of explosion - the emptier the tank, the bigger the bang.

Having sown the seeds of doubt, I can promise you that my next boat will be two stroke petrol powered!
 
Having had both Mk 1 and Mk 2 engines the comments so far match my own findings. The Mk 1 was smoother but inherently relient upon a pair of well charged batteries to get it going astern. The dynastart is cracking for getting the engine started and the going backwards to reverse thing is very easy to get the hang of. Dry exhaust is a bit of a pain and needs a very good flexible (like modern cars have) to avoid cracks as they age. Exhaust can also coke up and requires cleaning out. The engine it's self does not coke up but a ready supply of new plugs resolves most problems. Fuel quality is also important and avoiding water in the tank is fundemental. The Mk1 electrics look Heath Robinson but are actually fine. With the Mk1 I devised a 4 battery system with switches that allowed me to change between pairs (house and start) so that I always had 2 good batteries for starting. Once you understand that the electric controls put the batteries in series for starting and parrallel for charging you can start to understand what is going on. The Mk2 (mine is 16 Hp) is much better in the battery charging / normality stakes and of course is still running when you go astern. The gearbox also allows for a slower turning prop. They are fundementally a good engine and just take some understanding and learning. I would say stick with it and learn as much as possible about them. PM me if you need any more info.

Yoda
 
I agree with all that has been said. Just sold my yacht with a Dolphin 1 - had it for 18 years. The Dolphin was probably at least 25 years old and will probably go on for another 20 years. No trouble at all switching from forward to astern. Never let me down.
 
I had a Mk1 engine. Main problem was that the dynastart did not generate much power, so an additional alternator took care of this. I added a remote control, basically a switch box plugged into a caravan style connector. This allowed me to stand and steer, and control the engine from any point in the cockpit.
 
Once again, many thanks to all, very positive and interesting!

I am feeling a bit more comfortable about things now. To Re-Fueler, yes I know it is common in big ships, but thankfully, they are manned for the most part by highly skilled professionals........not some tottering old body like me! /forums/images/graemlins/grin.gif
 
I too had one in a Mystere during the 80s. Mixed feelings though. No problem with the complex relays involved but I did see problems with corrosion of the wiring loom contacts. Had to replace the cylinder head when the water jacket combined with the combustion chamber, also a new carb.
It also suffered fuel starvation for which the cure was to leave the fuel filler cap off when using the engine and blow down it when the revs began to falter.
I was pleased to have a diesel in subsequent boats.
 
Agree with previous comments. Had one for over 10 years-no trouble. Used to take it home each winter! Fitted a water cooling kit and wet exhaust-even better then!
 
The full story covering the remarkable 50 year production life of the RCA Dolphin engine may now be read on line at the Isle-of-Wight Vintage Motorcycle Club website, iwvmcc.co.uk

Please look in the “EXCHANGE” section where “The RCA Engine Story” is the second item, just under “Calming a Gold Star.”

(Or you could try this link)
http://www.iwvmcc.co.uk/exchange.php?active_page=&exchange_id=20

Many pictures of the manufacturing process may still be found in the “GALLERY” section dated 5th Sep 2005. (3 layers down!)

You will read that the “Dolphin” was just one of many interesting versions of the engine that I designed in1955 and manufactured until I was ousted from my own company in 1980!

The fourth chapter includes the recent company purchase by Glyn Jones and his future aspirations for the Dolphin, with contact addresses for the supply of parts, repairs and service.

My best wishes to all Dolphin owners! Peter Hogan 26/04/2009
 
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