As some of you know already I have purchased possibly the oldest Seal 28

As I expected the engine and gearbox needs replacing. The present engine is the original a (Bukh 20)

I am told these are no longer made. I am now looking for a possible replacement has any one,
any knowledge of doing this and any suggestions on what to replace it with.

I'm looking at possibly another Bukh, Volvo, Yanmar do you have any knowledge of doing this.

Ray (Sealoner)

Ray
What makes you think the engine and gearbox need replacing, they may be old but it is unlikely they have been used as much as a car for instance.
There is not much wrong with a Bukh 20, so long as the spares are available.
You have probably already had estimates, but what would the cost of overhauling the current one come to.
Have you considered doing it yourself.
I think that would be my first choice.
A new engine of similar spec as the Bukh is going to be £5000 plus. In 2006 my Beta 20 was £4000 with basic fitting (adapting engine beds fitting and alignment with the shaft) and I was lucky because everything married up with the old.
You may need to consider, exhaust, water inlet, wiring, throttle and gear controls, prop shaft coupling, engine beds width height and angle.

Mike

---

Mike,

The Engine has very little compression although no smoke I have had one engineer down and having gone through the engine we have various other concerns like bolts and studs that have corrosion on them. The gear box is the original type and although I could make a bracket to fix the current problem (No Reverse) Im told I am unlikely to get spares for it. If I bought a new Gearbox it would not fit the block as they have changed.

I intend to take the boat over to France and the channel islands in the summer so want to be 100% confident in the engine. so I am thinking of a Volvo. But am waiting for the engineer to confirm it is possible to fit it. This will solve my problems for some years hopefully. Im also waiting for prices on a Yanmar and a Bukh 20 Recon or a 24HP New (20 no longer made). I am also trying to find a dealer round here that dos Beta engines

I intend to do a much as possible my self with the help of two friends who are far more experienced than me (Some would say that's not hard)

Have you sold your boat yet.

regards

Ray

Just to update any reader My Boat Sealoner now has a nice new Beta engine and all beds, Sound proofing, Water, Fuel, Exhaust system, plus prop, prop shaft, seals and cutlass bearing were also changed.

I decided to replace the whole power plant in the end and she runs like a dream able to achive 6.5knot through the water.

If any one is interested it took two of us two working weeks bout some days were 12hr ones.

(Mike what size prop do you have on your Aztec ?.)

Ray

Hi Ray
My Prop is 13x9 3 blade

Mike

---

Thanks for the reply. After sending my update this morning I spotted your earlier reply to another topic were you stated it.

I decided to buy 25 HP with a 14x9 prop (Having taken off a 16xSomething.

I don't expect any more speed but a quicker pick up and a bit more boast when slipping of the mud or beech.

and an engine that's not working quite so hard.

My immediate impression is how quite the new one is.

When I visited your boat, it seemed to have more room between the steps and the table were you able to move the steps back to the stern or have you got a ladder instead of steps. I apoligise for my cheek

Ray

Hi Ray
I believe I was once told an inch on the prop (diameter or pitch) is equivalent to approximately 200rpm. (inverse proportion)
My engine revs up to 3600rpm, so your engine should rev up to about 3400rpm. Given the same gearbox.
It would be interesting to see if this is correct.
My steps are in the form of a moulding, and each tread is on alternate sides, that way the steps can be more vertical. You can just see one side of the steps in this photo.
http://www.swatchway.pwp...c_Seal_28_for_sale_3.JPG 

Mike

---

Not tried taking her up to full speed yet but with slightly more hp will it still be true?

Ill let you know later in the year.
Thanks for the picture of the steps.

Due to slightly smaller engine and remounting the engine I think I will be able to move the steps into engine bay by three or fore inches and if I follow you steps it could make a big difference. The present steps need some work so now will be the time to change them.

Thanks for the info.

Ray