Ideal YSM8 engine replacement

[najsmith]

Hi Forumites,

I'm considering replacing my existing 35yo YSM8 with a new or re-con engine, however I wish to avoid undertaking any surgery concerning the engine mounts, P-Bracket etc.

She currently has a 7/8" shaft.

Can anyone point me to a make/model of diesel engine that would be able to effectivley "hot swap" what i already have? I accept i might need a new prop/shaft based on increased HP but the major costs are likely to come form having to grind out cross members and create new mounts.

Answers on a post card

Cheers

NAJS

 

[Spuddy]

Well, I'll kick off. The Beta range will modify the engine mounts to suit your existing installation.
Dunno about shaft size implications I'm afraid

 

[NickRobinson]

You'll enjoy the quiet, whatever you choose-

I went from a YSM8 to a QM15 but by changing boats.

I'm sure you have factored in any cockpit surgery to all for the higher (non-horizontal) new engine-

N

 

[Tranona]

Hi Forumites,

I'm considering replacing my existing 35yo YSM8 with a new or re-con engine, however I wish to avoid undertaking any surgery concerning the engine mounts, P-Bracket etc.

She currently has a 7/8" shaft.

Can anyone point me to a make/model of diesel engine that would be able to effectivley "hot swap" what i already have? I accept i might need a new prop/shaft based on increased HP but the major costs are likely to come form having to grind out cross members and create new mounts.

Answers on a post card

Cheers

NAJS

No modern engine will be a simple replacement. The basic architecture, that is mounting footprint and output centre of shaft is completely different. You need to change everything controls, prop, exhaust system. Modifying the engine beds is the least of the problems cost wise. You can either install new beds or have a metal framework to mate your new mounts to the old beds. You may get away with your current shaft, but the stern gear will probably need replacing anyway so suggest going up to 1”.

Beta or Nanni 10 or 14 are arguably the best choice and both will advise on mods necessary to fit your boat.

 

[najsmith]

Good point - I am having someone fabrciate a large access hatch out of the cockpit sole which will involve the sole raising.

Really can't face the idea of a shaft size change...that would mean a P-bracket change... :'(

 

[Tranona]

Good point - I am having someone fabrciate a large access hatch out of the cockpit sole which will involve the sole raising.

Really can't face the idea of a shaft size change...that would mean a P-bracket change... :'(

No. You will only have to change the bearing. Usually the outside diameter of the shell is the same size, just the bearing liner is different. Even if the bore of your P bracket is non standard you can get a composite bearing machined to size.

 

[Sandy]

What are you planning to do with your old engine? I have an Yanmar YSB8G and might be interested in parts.