Mercury XR4/Magnum II dressed up as 2.5 Offshore... Need advice!

[sameri]

Hi All,

First time post. I had my eye on a nice (cheap) little ski boat that had a Mercury 2.5 Offshore mounted on the back. (I did a heap of reading up on the 2.5 Offshore's on this forum before I went to look at the boat).

Went and looked at it yesterday, removed the cowl and was a little confused by the "EFI 2.4" stamped on the intake!

I took photos of the motor and serial number. Serial number was 0C292561 (at least I think it was... there were a few numbers stamped on it) which came up in a serial number search as a 1990 Mercury 150HP XR4/Magnum II.

So my questions are:

1. Were the Cowls interchangeable leading to the possibility that this "2.5 Offshore" is actually just an XR4?
2. Does this motor look like an XR4?
3. If it is a 150HP XR4, were they a crackin' motor? How would they compare to an Offshore? I had my heart set on an Offshore after all the reading I did :-(

[mach351]

Remember....these motors are all 20-30 years old now. Lots of changing and swapping.

That is a 2.4 EFI. Xr4’s were carb’ed. Not saying someone couldn’t have put efi on the xr4. Only true way to know if it’s an xr4 is to pull a head and check the bore. If it’s 3.375” and steel, it’s an xr4. Other 2.4’s were chrome bore. The cowling is what we call a “260” cowl. And yes that was a 2.5.

Kinda a hodgepodge motor. Doesn’t mean it isn’t good. Practically ALL of my motors are hodgepodge. If it runs good use it. If you want more speed later, a later model (96-99) 200EFI 2.5 will bolt right up and run great.

[sameri]

Cheers mate. That's pretty much the story I got from my local Mercury mob.

They said the Serial number that was stamped into the head is for an older 1990 150HP 2.5 carby power head (as you said). Apparently they didn't stamp the engine numbers in, they were meant to be found on a sticker (not sure if true?). So the fact that it’s stamped in would indicate the original 2.5 EFI powerhead blew up at some stage and has been replaced with an older 2.5 carby powerhead but all of the EFI equipment was bolted on from the original motor. And given all EFIs used the same computer it is stamped as 2.4 (also as you said). So long story short is that it is PROBABLY a 2.5 150HP carby powerhead with all the bolt on bits from a 260HP EFI motor. Not surprising I guess given the age of the motor.

Biggest problem is that I can't get the starter motor to throw so only guarantee that it runs is the word of the guy selling it...

[mach351]

There’s a ton of different computers for different 2.4’s and 2.5’s, and their different hp ratings. The powerhead May have been swapped, but the most likely scenario is that some swapped that cowl onto your motor. It’s a common upgrade to go-fast guys to put a lightweight 260 cowl on their boats.

[tlwjkw]

that number stamped on tha block comes out as a 2.0 150 motor per merc website .. tha shape of tha block cylinders make it pre '91 2.0 or 2.4.. not a 2.5 anything!... gonna need ta pull a head ta find out for sure..
2.0 = no doubt identifying it....
2.4 steel = 150
2.4 chrome = 200

there will be a "build date" stamped on tha block half, at base of number 2 where case splits.. kinda right behind tha bend in tha timin' arm... be 1/8" numbers.. m/d/yr.

[W2F a V-King]

Also I believe the XR4 2.4 motor was a vertical reed motor vs the 200 horizontal reed.

Don't buy it without hearing it run, and at least a compression test. Then, Better yet take it to the water for a ride...

[tlwjkw]

Also I believe the XR4 2.4 motor was a vertical reed motor vs the 200 horizontal reed.

'87/'88 were.. went horizontal in '89.......... also went ta 40 amp same time.... several things ta question.....
tha wood "spacers" with screws are a nice touch.......

[RIVERRUMMER 70]

just a fish motor ....not hi po in any way other than cowl.

[Glastron1987]

That is a confusing one. The Mercury website lists that serial# as a 2.0L 150, and the marineengine website lists it as a Mercury / Mariner (135 / 150 / 175 200(2.5l) Xr4 / Magnum II). Also, to make it even more confusing as one above mentioned the XR4 was a 2.4 liter motor not a 2.5 liter. That serial number range does appear to place it in the early 1990's. By the picture it is obvious that the motor is fuel injected.

I have a shop manual that does indicate there were some fuel injected (XRI) 2.5L motors between 1991 and 1993. Which is the range of years where Mercury was switching over from the older 2.0/2.4L blocks to the 2.0/2.5L fatblocks.

My understanding of the Offshore designation is really just the 25" (XL) lower unit instead of the 20" (L) lower unit.

In any case, if you can get a good compression test on that motor, it just may be a good one.

[tlwjkw]

That is a confusing one. The Mercury website lists that serial# as a 2.0L 150, and the marineengine website lists it as a Mercury / Mariner (135 / 150 / 175 200(2.5l) Xr4 / Magnum II). Also, to make it even more confusing as one above mentioned the XR4 was a 2.4 liter motor not a 2.5 liter. That serial number range does appear to place it in the early 1990's. By the picture it is obvious that the motor is fuel injected.

'91 was tha only year of tha 2.4 "fat block" and first year of tha 2.5.. all 2.0's were "fat blocks" from '91 up until tha 2.0 went away in tha 2000's somewhere...

just that that parts list/manual covers all of tha above... ya need ta know which one is yours!.. think they did that on purpose..

I have a shop manual that does indicate there were some fuel injected (XRI) 2.5L motors between 1991 and 1993. Which is the range of years where Mercury was switching over from the older 2.0/2.4L blocks to the 2.0/2.5L fatblocks.

first efi came in '87 and was badged "LASER".. Laser went away in '89 and all were badged XRI's till mid '90's.. then changed to EFI badge...

My understanding of the Offshore designation is really just the 25" (XL) lower unit instead of the 20" (L) lower unit.

that's only with "PRODUCTION DIVISION"... offshore from HIGH PERFORMANCE DIVISION is completely different and what you are lookin' for!



In any case, if you can get a good compression test on that motor, it just may be a good one.

maybe this helps ya little, maybe not?.............

[Mike Nass]

Your engine in question is NOT a hi performance offshore... its is either a 2.0 or 2.4 liter fishing engine, as stated you would have to pull the heads to confirm which... its definitely not a 2.5 of any sort... i would bet its a 2.4... It's a regular production style engine, nothing hi performance at all except it does have a hi performance 260 style/offshore light weight engine cowl... true offshore Hi performance engine has a different gear case, mid section exhaust can, Exhaust plate, swivel bracket and the power head itself would be an unpainted block 2.5 liter fuel injected... cheers

[Krazymaan]

Thats a super nice cowl. But in general you would want to put a 150hp cowl with a 250hp motor hiding under it so you can kick some ass. Not a 250hp hi perf cowl with a 150hp hiding under it, its your ass thats gonna get kicked.
We often hear things are backwards in Australia, thanks for more proof
But if its a good runner and a decent boat for a good price. It could be lots of fun.

[sameri]

Thanks for all the responses guys! I got busy after posting my original question and forgot to check back!

So just to report back, I ended up buying the boat without seeing it run... Risky I know but I like to live on the edge...

Turns out it was a good gamble as all it NEEDED doing in the end was to drop a $60 second hand starter motor in and away it went good as gold!

Then just for good measure I replaced all the fuel hoses (fair bit of cracking present), installed a remote fuel filter and bypassed the on-engine Mercury one (can anyone tell me if this is a bad idea?), changed the impeller and gearbox oil, popped in a new electronic fuel pump as the terminals on the old one were dodgey and finally a fresh set of plugs just for good measure. Total cost of the boat, motor, trailer was $4000 and all the work to get it back to an acceptable condition ended up around $200. So a total cost of $4200 for a tidy runner is really good here in Aus so I'm a very happy man!

Boat handles well and has some real poke so really don't care what the motor is deep down Hits just over 50mph at top speed and easily pulls 2 skiiers out of the water with a few people in the boat so more than enough for what I want.

One thing it's missing that I'd like to add is a tilt/trim gauge so was wondering if anyone had any pointers on what's required to install one?