Arona 2 cylinder in Hartley Queenslander

[Bu Jim]

Hi to all
I am a first-time poster.
I need some help/advice regarding this motor. Firstly it has two rubber bungs in the head next to the injectors what are they for? Secondly, it doesn't have an oil filter.

The motor via the gearbox drives the propeller shaft by a chain. It would appear that the propellor shart has moved forward as the key on the shaft is visible in front of the cog. When in gear there is no drive, the boat just drifts.

I am having difficulty figuring out how that could happen, how does the prop shaft move forward when there is a propellor on the end of it?

Any help would be greatly appreciated.

Cheers
Jim

[deblen]

Never heard of Arona,so I had to Google.
Is this "Lombardini" like your Arona.

https://iluka-nsw.australialisted.co...ry/18253053/1/
Cheers/Len

[Bu Jim]

Thanks, Len for the reply, and yes Arona was taken over by Lombardi in 1983. The motor in the photo is not the same model that I have I think but close enough.

[skipperpete]

Hi BuJim, I’m pretty sure the rubber plugs are the Arona/Lombardini solution to the indirect injection cold starting problem. The idea is to pull out the plugs, pour engine oil into the measuring cup section and replace the plug and try for a start. The oil from the cups enters the cylinder via the intake manifold and effectively increases the compression.
The oil filter is a gauze or fine mesh metal strainer under a square headed plug, just wash it in degreaser or solvent ,put it back in the hole and replace the plug.

[Bu Jim]

Thanks Pete that has been a great help relief to know what the rubber bungs are for.I will look for the square bolt on the block.
Any thoughts on the prop shaft?

[skipperpete]

Not a bolt, a plug with a square head for a spanner, I think it’s near the lift pump on the same oil gallery as the pressure sender. The propshaft is a whole other thing, the standard gearbox was a Hurth but there’s a chance it’s an old Technodrive but one thing’s certain, the shaft should be solidly held by the coupling. The drive plate could be the culprit too and the big worry is that you have an ancient arona transmission ahead of that chain drive. Post a pic of what that gearbox and chain looks like!

[Bu Jim]

Thanks again Pete
I will post photos when I have figured out how to do that.
I have tried to attach a photo but it doesn't seem to have worked.

[Bu Jim]

Right well that has worked unfortunately I haven't got any photos of the gearbox but will post as soon as I can. Here is a photo of the motor which is under a hatch in the cockpit.Ok I am having problems with my internet at the moment so I will attempt to upload the photo asap.

[skipperpete]

Yes, that drive setup is as quirky as it sounded in your description and what’s really amazing is that it’s probably been working more or less ….well,…… for 20 or 30 years. Running a dry triplex chain must be as noisy as hell and it’s not clear how the thrust and side load are dealt with on the propshaft. The gearbox is visible enough for me to suggest it’s not a Hurth OR a Technodrive but it must be a tough little bugger to tolerate being loaded vertically downward by that chain. If the little Arona has rubber engine mounts, I’d be even more impressed, although it would make sense to hard mount it rather than having it jumping about on soft mounts. If there’s no logical way to change the existing setup to a more direct and conventional gearbox to propshaft arrangement, you could make it a lot quieter if you swapped out the triplex sprockets for 3 row pulleys and got an industrial 3 in one vee belt and an idler, the fishermen here use that setup to run trawl winches that take 100hp so the Arona would be way too small to make a triplex belt slip…. And you’d never have to oil it.

[Bu Jim]

Yep the engine is mounted on rubber mounts and your idea on the pulleys and belt sounds good as it is very noisy. I will post some more photos once I take them. How the shart has moved forward has me scratching my head. The motor and gearbox are at least 30 maybe even 40 years old the motor was taken out and reconditioned about 8 years ago and has done nothing since then.
Thanks Skipper Pete your help has been much appreciated.

[skipperpete]

The nature of a propeller shaft is to move forward and normally the coupling and rear gearbox bearing resist the thrust , but in your instance it looks like the sprocket is loose and I assume there’s some kind of thrust block that stops it that’s not visible in the photo’s. You can fix this by locating and tightening the set screws ( 2 of em) somewhere on the sprocket OR replace the whole lower sprocket with one that has a taper lock or fenner lock hub to lock the sprocket onto the shaft. You don’t mention whether the chain and sprockets spin when you put the gearbox in ahead or astern, this might be a gear box problem, not a shaft problem.

[Bu Jim]

The last time I ran the motor turned into a bit of disaster inasmuch the throttle cable ceased and the gear change mechanism fell to bits and then the exhaust broke off at the manifold. All of this happened after slipping the mooring. Resulting in the vessel having to be towed back onto the mooring from where it had drifted too.
So all that to say the chain was spinning around but the prop was not driving the boat ahead. Now having lifted the sole so as to be able to view the bottom cog and shaft they do all turn while the motor is off and the gearbox is in neutral. There are two frames about 30cm apart one has the stuffing box and the other would appear to have a bearing. I am assuming this to be a thrust bearing. Could that be the problem? How do they grip the shaft?

Once again Skipper Pete thanks for your help.
I am in Melbourne and the boat is moored in Hobson Bay Williamstown. Whereabouts are you in Australia?

[skipperpete]

Hi BuJim, I’m originally from Melbourne but now travelling regularly between Ballina NSW and Brisbane.
I don’t know how your sprocket is secured on the propshaft but a first guess would be 2 grub screws or maybe 2 square headed set screws like old style couplings have, either way, the sprocket needs to be a fairly tight fit on the propshaft. The thrust bearing could be a simple Plummer block, again… secured with a couple of grubscrews. This is not an ideal arrangement but with such low horsepower, the stresses are minimal. Is there any chance the propeller is shelled up? If the shaft is turning but there’s no thrust, that’s a distinct possibility.

[Bu Jim]

Hi Skipper Pete I will be heading to the boat in the next week or so and will have a look at the sprocket and thrust bearing. I will also take some photos. The boat had been motor sailed over to St Kilda and around Port Melbourne and was driving well under the motor alone so I think the prop isn't the issue. Once again thanks for your help. I will be in contact once I have been to the boat. Cheerio for now Jim

[skipperpete]

Originally Posted by Bu Jim

Hi Skipper Pete I will be heading to the boat in the next week or so and will have a look at the sprocket and thrust bearing. I will also take some photos. The boat had been motor sailed over to St Kilda and around Port Melbourne and was driving well under the motor alone so I think the prop isn't the issue. Once again thanks for your help. I will be in contact once I have been to the boat. Cheerio for now Jim

Haha, enjoy the bay Bu Jim, I spent the early years of my life sailing around St Kilda and that part of Port Philip bay.