Atomic 4 replacement - SailNet Community
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post #1 of 5 Old 06-13-2005 Thread Starter
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Atomic 4 replacement

Does anyone have any comments on Beta Marine''s Kubota replacement for the Atomic 4.
I do not want to rebuild my "4". I want to go diesel, any body have any other suggestions. Kubota is in $ 7,000 range (if I install)
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post #2 of 5 Old 06-13-2005
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Atomic 4 replacement

I replaced an Atomic 4 with the Universal marinized Kubota three cylinder 18 hp. diesel nine years ago and have been extremely happy with it. It starts so quickly you can''t even hear the starter spin. Good luck.
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post #3 of 5 Old 06-14-2005
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Atomic 4 replacement

My brother and I did this exact replacement on his Ranger 33 last year. It really ws a pretty easy switch, although given some of the changes we had to make, the cost was far greater.

I won''t go into why the Beta was chosen, suffice it to say that after much research, it came out on top of the rest. The biggest selling point was that ALL the engine systems are lead to the "front" of the engine leading to very easy access to everything if you have removable companion way steps.

We decided on the switch when his A4 finally started leaking water from both the head and the pan. At that point it was obvious that the A4 was on its last legs.

We began by shopping around the Beta engine. it turns out that here in San Diego we have the boat show in January. We realized that our local Beta distrributor gave heavy discounts if you buy the engine at the show. So we went to him and asked for the show price since we wanted to get started on ther switch ASAP. He gave it to us.

I''m not sure what the final price was, somewhere in the high 5''s I think, including the freight to the club where his boat is.

While we waited for the new engine to arrive we removed the old A4. Really wasn''t that difficult other than the A4''s engine mounts were pretty well welded together. We ended up with a cold chisel on two of the mounts as well as the coupler to the shaft.

The engine popped right out and we dingy dragged the boat over to the manual hoist at the club and hauled the old A4 into the back of my truck.

We cleaned up the engine compartment and did a little LP and glassing to fix up previous owners cuts and holes and poor "cabinet" work in the engine compartment.

We also, spent about $1700, and two weeks rewiring the entire electric (12 volt and 110) system. We figured that with the new engine we might as well have the whole system cleaned up. The Beta comes with a very straightforward wiring harness, with just one sealed bunch of wires coming into the engine room.

So now we had a very clean and sleak engine room, At that point we realized that a new fuel tank would be necessary. Obviously the old one was just that, old. It looked OK, not much corrosion but we couldn''t inspect the interior, further, it wasnt designed for diesel, i.e. no return. It also had been having problewms with the vent (pluggged) as well as the fuel gauge.

We measured out the old tank and ordered a new one from off the shelf. We installed a new vent, and all new hoses, a solid ground, and a new gauge.

Issue #1:
The Beta sits lower than the A4 and we needed almost two inches of risers under the new Beta motor mounts. We ground down the old surface were the A4 mounted and put down some 2 X 4''s with 5200 and then glassed the whole area with 12oz mat and West epoxy. Turns out that you can get motor mounts that handle this issue but they got very expensive, very quick. We did all this in about 2 hours with about $25 in supplies. Again we sanded and faired the whole area and painted it all up. It looked very professional and very clean.

We dropped in the new motor (using a local boat hoist) and went to town on the adjusting. Pretty easy once you figure out the details of the engine mounnts. We laged bolted the new mounts into the new glass/2x4''s, with adequate lifeseal. We added a new Racor 110A (which we are both partial too, for ease of draining and for changing the filter, plus the filters are cheaper than the others). And a new standard raw water filter.

Now the tough part, attaching the new coupler. The old one was history. We got a new plastic flexible for the coupling between the shaft and engine. Very easy. Just make absolutley sure that the engine alignment is perfect with the shaft. Thats a whole different discussion about how to properly align an engine with the shaft, etc. We were lucky that we have a friend who comissions sailboats for a living and he came over and coached us one morning (in exchange for breakfast and beer).

So the new fuel lines are connected, the new raw water lines are conncted, the exhaust systme is connected. New throttle ($35) and shifter ($54) cable from the pedestal are connected, and the electric harness is connected. The Ranger used to have all the engine controls and gauges insidee the companion way (inconvenient for the driver), we moved all that back behind the pedestal in the cockpit when we rewired the boat. The Beta comes with a very nice control panel. So we cut a whole in the lazaret for the new panel, we already had all the necessary wiring led back there.

Cheeck all the engine fluids and fire this puppy up.

It started right away, the fuel was flowing, the exhaust water was flowing, oil pressure and temp were perfect, all the electric worked.

So we shut down and packed up, cleaned the boat that was a mess for the last two months, straightened everything up and went for a spin.

Getting out of the slip was tricky, my brother had reveresed the shift cable connection (or I should say that the Beta revereses the direction that the cable attaches) so forward on the pedestal shifter was reverse on the engine. No problem. On the water and ready to open up the new engine. Well e brought her slowly up to 3000 RPM and she didn''t like it much, like she felt underpowered. Further, we were barely pulling 3.5 knots. Something was not right.

We killed the engine and I jumped over to make sue there was no fowling on the prop or shaft. She was clean. Then we realized that it was a prop issue.

Issue #2:
You will need a new prop. Don''t ask me why I don''t know all those issues. Here''s the jist of it though. The old prop was wayyyy to small for this new Beta. I think we ended up with an extra 2 inches in diameter and another 6 degrees of pitch, needless to say this required a new shaft as well. A new folding prop from Martek ($900) and a new shaft ($850) as well as a haul out and a new packing land and strut bearings (another $700). now we were on our way.
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post #4 of 5 Old 06-16-2005 Thread Starter
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Atomic 4 replacement

Thank you for the info, Beta did mention a 3 bladed prop would be necessary. I think i will continue to "look around" for an alternate. I have time.I am preparing for 5 months of sailing ,starting in October
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post #5 of 5 Old 06-16-2005
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Atomic 4 replacement

I recently repowered my old YSE12 with a new Yanmar 3YM20. Ultar low vibration. Nice motor. I looked around at others and it just made sense. Keeep in mind it isn''t just the cost of the motor. It''s:

Fuel tank and hoses.
Fuel filter.
Prop shaft.

One tip that I would pass along. Vetus makes a product called the bullflex coupling. It couples the engine to the shaft, but allows for up to 2 degress of mis-alignment. If you are installing the engine yourself this little unit can make life so much easier!
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