Diesel outboard

great news . 29 kmh is probably the fastest diesel outboard in australia. It will only improve from here on. you are better off getting a few different pitch props. Raid the scrap bins at the local boat places. If you keep turning down diameters the prop will lose to much blade area. You need to adjust the pitch not blade area. I would love to come and have look if possible and get a price on the 60 hp version.

 

Sorry mr e. I did'nt realise you had already mentioned the diameter loss.

 

No worries WP 23, I am as interested in this as many others no doubt are, but the "test" is probably not being done in ideal conditions, without a tacho etc, and a hull that likely is not suitable.

 

If your boat went ok with a 55hp 2 stroke you will need almost twice that from a diesel to get the same performance
Would be my guess

 

Great to get the motor mounted and working....
Just wondering what sort of price you ended up paying including the shipping, was it more or less than a standard 4str petrol ob of the same hp in Oz?

Can't remember if you already said how long the OB took to be delivered from China?

Looking forward to an post running in update report.......

 

Where has harry gone. Hope he isn't drifting around bass
Straight.

 

Glug glug glug.

How are we all?
Life has been nice to me lately. Gee the vee twin motors are selling like hotcakes, the farmers love them. But as a consequence no playtime.

3 props for you to peruse.

1. Original- Replacable, Identifiable. 25 Km/h after adjusting trim.
2. From the 55Hp. As you can see, narrower blades but more diameter. 21 Km/h. As to the size and pitch I have no idea.
3. Original minus 10 mm off diameter so 5mm off each blade. Measurable, reproduceable and available. The difference is very small visually but an extra 4 Km/h in top speed. 29 Km/h. That's an 18% increase and I haven't feathered the prop yet, I've just left it as it came off the lathe so some further gains may be found there. I love changing things to see what happens, not just buying things, blindly fitting them and accepting the results as being the best we can get. Sometimes I can make things better but not always. One thing that did produce interesting results was the velocity porting- http://www.mototuneusa.com/thanx.htm. My Husaberg 501 could lay a 500m powerslide in 6th gear with full control at 100 km/h plus in the dirt. Wicked, I've tried it and proved it but as EVERY expert will tell you, it doesn't work.

There is a specific reason I am changing diameter and not pitch. Pitch means a whole new prop and how many till we get best performance? Diameter I can change and once I've gone too far I buy 1 new prop and machine to best size to suit my application.

There is another reason and that is photo 4. Those of you who recognize the boat builder and his history will know that high speeds and sensational deep water handling are a prerequisite for any boat he builds. The police had to confiscate one of his boats so they finally had something that could keep up! The Camcraft outran helicopters, planes and every boat they chased him with across Bass Straight coming back from Tassie with a 2 tonne load on deck. Cam's first words were smaller prop (dia).

So thanks for your advice but until proven otherwise, Cam's guidance has proven to produce positive results and I will continue in this direction for now.

The Chinese are clever. It's in the little things. One of the biggest problems with boat motors in general is the cold incoming water hitting a hot motor. Fuel condensation due to cold engine temperatures makes for a very short engine life as the lubricating oil is continually washed off the cylinder walls by the now liquid petrol. In a diesel, higher temperatures give better fuel economy, more power and less pollution.

My Runsun diesel outboard motor has two water pumps, one in the leg to supply the cooling water and the motor water pump like your car has. What I noticed is that my motor has an inbuilt re-circulating water system to keep the whole motor at the same temperature and allow faster warm up. Problem is, the thermostat seems to close off completely so I see no signs of whether the leg water pump is working and we have cooling water until the motor is hot and the thermostat opens. I then get clouds of steam coming out of the water outlet at the back of the outboard as 80 degree water is slowly released to atmosphere.

I found this a tad disconcerting as I like to know, you know? So I tapped into the recirculating pipe to create a tell tale and it works really well. Except now the motor can't get up to temperature from the constant coolant loss.

Hmmmm. Thinking thinking thinking, ouch that hurts! So how do I PROVE that the leg pump is pumping and the motor has coolant available even when the thermostat is closed and we have no visible signs of water flow?
A pressure switch would solve the problem but where do I find one? My background is I am an A Grade heavy industry automation and control sparky with appliance repairs thrown in. Allen Bradley or Square D and we are looking at several hundreds of dollars. Mate, it's a Chinese cheap motor, lets keep with the theme. Dishwashers and washing machines use pressure switches for water level control. $30 and positive proof I have water in my motor and no coolant loss. So that is tomorrow's project.

Thanks for your interest and I hope your water is flat and your fish hooks full.

Cheers Phil.

www.dieseloutboardsvictoria.com

 

Thanks for your update.

Have you got any videos or photo's of the boat underway?

 

I can't post my videos here, they are all over 10Mb. Have a peek here.
www.facebook.com/outboarddieselvictoria

Cheers Phil

 

That extra circulating pump has been on volvo and mercruiser engines for 3 or 4 decades.

 

Yep good old formula 24 came to oz and built under licence by the haines brothers many years ago.
Truly magnificent boat in the rough

 

If you chop diameter off and get the rpm you should have you wont know what pitch prop to then buy.
You also need to be sure you dont get the rpm from more prop slip

 

After watching your video I will stick with my johnson. That diesel is far to noisy for a pleasure boat. I can see a market in the aquaculture industry once it has proven its reliability.

 

It could be useful as a standby engine on a single engine trawler; fitting it to a small bracket on the stern would be easy enough. The big advantage is that it will run on diesel like the main engine.