Universal M25 diesel ID

[frogdoc58]

Hi All,

I am hoping that someone might be able to help me identify which model of engine I have.  Just an M 25 or a M 25XP.

Are there number on the block somewhere?

I have taken the engine out for rebuilding over the winter.  So, I have to figure out which gasket kit I need to order, etc.

Stay safe out there.

Paul & Judy o/b Windswept

[KWKloeber]

Pictures?   I can determine from a set/ different angles/locations.

It would sure help if you provided basic info!  Year?

The model number tag is stuck onto the top of the exhaust manifold (if it hasn't fallen off.)

[Stu Jackson]

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Just an M 25 or a M 25XP.

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Two easy ones:

1.  Size of HX  2" is an M25, 3" is an XP unless your PO changed an M25 HX to a 3" like many of us have

2.  Alternator bracket - if silver most likely upgraded on an M25, engine color most likely XP (unless an M25 PO painted the upgraded bracket)

[frogdoc58]

My boat is 1989, 34, tall rig, so I am assuming the motor is original.
If I can figure out how to attach photos, I will.
Thanks so far.

[Stu Jackson]

My boat is 1989, 34, tall rig, so I am assuming the motor is original.
If I can figure out how to attach photos, I will.
Thanks so far.

1989 would be an M25XP.

Photos?  See the 101 Topics:  third item there

Posting and RESIZING Photos 101  http://c34.org/bbs/index.php/topic,3701.0.html

[frogdoc58]

Pictures?   I can determine from a set/ different angles/locations.

It would sure help if you provided basic info!  Year?

The model number tag is stuck onto the top of the exhaust manifold (if it hasn't fallen off.)

...............
.............
Just an M 25 or a M 25XP.

.....................

Two easy ones:

1.  Size of HX  2" is an M25, 3" is an XP unless your PO changed an M25 HX to a 3" like many of us have

2.  Alternator bracket - if silver most likely upgraded on an M25, engine color most likely XP (unless an M25 PO painted the upgraded bracket)

What does HX and PO stand for?

[Stu Jackson]

HX = heat exchanger

PO = previous owner

Either engineer-speak or internet boating forum shortcuts.  Take your pick.   

[Ron Hill]

frog : If you have a 1989 C34 and it is painted bronze - look on the top of the coolant reservoir (just aft of the "radiator cap") and there should be a decal from Medalest in Oshkosh Wis. saying it is a M25XP engine.

A thought

[frogdoc58]

Hi All,  well, I figured out what engine I have the old fashion way.  V=pi x r2 x H.  In other words figuring out the volume of a cylinder.

So, I have a M 25XP.

Thanks to all for the helpful input.

[Ron Hill]

frog doc : Good for you - but taking off the head, measuring the piston diameter, and length of the stroke is a bit much for most of us; just to determine which engine we have!?!   

BTW, Catalina stopped installing M25 engines with the start of the 1987 production. Except for maybe a hull or two? the 1987s, 1988s, & 1989s C34s all have a M25XP engine at production.

A thought

[KWKloeber]

measuring the piston diameter, and length of the stroke is a bit much for most of us

Apologies for the late post,  I had "posted this" long ago but I apparently fubar'd something and I just noticed that it didn't actually go thru.

The easiest way to absolutely determine is not with a ruler but with a flashlight.  The displacement is cast into the block, above the secondary fuel filter.

855cc= M-25 (picture below.)
9nn cc = XP engine (M-25XP or M-25XPA or M-25XA(C) ) 
(The caveat is that this naturally doesn't apply if someone did a major overhaul and bored out the cylinders) 

The XPA has a separate oil pressure switch (not on the block, but on a bracket bolted to an unused port engine mount hole) and a circuit breaker (feeding cockpit panel) and preheat solenoid mounted stbd side above/behind the fuel pump.

The (C) is the XPA engine, only with a slightly different (C = Catalina) wiring scheme.

[Ron Hill]

frog : When all else fails  if you remove the injection pump there is the Kubota Block number stamped into the casting.

Hard to believe that you would have to go that far - as the are so many other ways to tell an M25 from a M25XP !!   

A thought

[KWKloeber]

Ron

Ok, I'll bite on that.
Other than a flashlight to read the displacement on the block what other way is definitive.