XR2 Compression and RPM Question

madrat · 09-02-2012, 10:26 PM

Hi folks,
Considering the purchase of an older (Late 80's?) XR2 motor, I have a spectacular record of buying knackered outboards and would prefer not to repeat this trick again!

The engine has not been used for 18 months but I'm sold its not had a hard life, can I take a meaningful compression test without running it up to temp and getting the bore's lubed up? And what should I be looking for in terms of compressions? 130psi + I would guess? What sort of variation should be tolerable between cylinders?

The owner mentioned the boat (A big fletcher) would max out at 55mph at 5700rpm, I'm assuming this motor would have a 1.86 ratio leg and with the 21" prop fitted those figures sound about right to me?

I'm guessing the big hull is preventing it from reaching the rev limiter, or does that point to it being down on power?

Any advice appreciated on this one!

Hydrostream · 09-02-2012, 10:57 PM

Quote:

Originally Posted by madrat

Hi folks,
Considering the purchase of an older (Late 80's?) XR2 motor, I have a spectacular record of buying knackered outboards and would prefer not to repeat this trick again!

Then maybe an XR2 isnt the best choice,

cant say many of them have had an easy life! Lots of them kicking about from the 2lt/ 4lt & OCR days. So its pretty sure to have been raced at some point.

But thats not saying it isnt a healthy motor... PSI should be high, ive tested some at over 160

Its not reving on the fletcher because it isnt propped to rev. probably a good thing in this case. Rev them conservatively and they last ok, turn them up and they show their insides pretty quick!

Theres no limiter on them either.

madrat · 09-02-2012, 11:50 PM

Cheers Hydrostream, caught in my usual trap of not being in the market for anything reliable!

I believe the engine is original to the Fletcher so if that's correct and its been used for skiing rather than raced to death then it might be a good one. Its certainly been on the Fletcher for the last 10 years.

Renegade · 10-02-2012, 12:06 AM

I would seriously suggest looking into what parts you can still get hold of for that motor, not 2nd hand but new.

Hydrostream · 10-02-2012, 01:09 AM

Quote:

Originally Posted by Renegade

I would seriously suggest looking into what parts you can still get hold of for that motor, not 2nd hand but new.

Most of them I would think, no?
At least all the wearing parts anyway

OCRDA · 10-02-2012, 03:59 AM

Quote:

Originally Posted by madrat

Hi folks,
Considering the purchase of an older (Late 80's?) XR2 motor, I have a spectacular record of buying knackered outboards and would prefer not to repeat this trick again!

The engine has not been used for 18 months but I'm sold its not had a hard life, can I take a meaningful compression test without running it up to temp and getting the bore's lubed up? And what should I be looking for in terms of compressions? 130psi + I would guess? What sort of variation should be tolerable between cylinders?

The owner mentioned the boat (A big fletcher) would max out at 55mph at 5700rpm, I'm assuming this motor would have a 1.86 ratio leg and with the 21" prop fitted those figures sound about right to me?

Unless you want to race it in a particular class or want something to costantly maintain as a hobby I would suggest you look for a Yamaha.

I'm guessing the big hull is preventing it from reaching the rev limiter, or does that point to it being down on power?

Any advice appreciated on this one!

Unless you want it to race I suggest you look for a Yamaha.

madrat · 10-02-2012, 06:56 AM

A Yamaha 200 V6 would be lovely but its just beyond budget, the XR2 would be affordable for now with the intention to change out later on. I'd always assumed spares were readily available for these engines either New or Used given their popularity?

I'm not expecting miracles for the money and I'm quite used to keeping tools in the boat! I'm mechanically very competent, just new to the 2 stroke's!

Thanks for the opinions guys...

grandmas denture · 10-02-2012, 08:58 AM

Quote:

Originally Posted by madrat

... Considering the purchase of an older (Late 80's?) XR2 motor...

Quote:

Originally Posted by Hydrostream

Then maybe an XR2 isnt the best choice,

cant say many of them have had an easy life! Lots of them kicking about from the 2lt/ 4lt & OCR days. So its pretty sure to have been raced at some point.

... im not sure you talkin about the same type of engines

... late 80s xr2 with clamshell cowling were stock 150 with minimal modifications which provides ~10% more power just below 6000rpm

driver510 · 10-02-2012, 09:07 AM

That clam xr2 was around 1984-1986 in 1987 it went onto the thin drop over cowl type

Renegade · 10-02-2012, 09:31 AM

Quote:

Originally Posted by madrat

A Yamaha 200 V6 would be lovely but its just beyond budget, the XR2 would be affordable for now with the intention to change out later on. I'd always assumed spares were readily available for these engines either New or Used given their popularity?

I'm not expecting miracles for the money and I'm quite used to keeping tools in the boat! I'm mechanically very competent, just new to the 2 stroke's!

Thanks for the opinions guys...

The xr2 was mainly for the european race market.

madrat · 10-02-2012, 10:29 AM

Sorry guys I'm getting confuzzled! Told you I didn't know anything about 2 stroke's! Its not an XR2, but a 2.4L Carb'd 200hp oil injected engine.

Its the one in this advert
http://www.boatmad.com/forum/showthread.php?t=18676

Not sure if that changes anything...?

driver510 · 10-02-2012, 10:34 AM

That engine is around 1984-1985 compression will be around the 120-130 psi

The Docta · 10-02-2012, 10:38 AM

There are at least 3 different XR2s right??

Which one is being discussed here. Based on age (late 80's), I assume it could either be a mercury hi-perf XR2 (150hp 2.0 bucket cowl - as used in 3c eg http://boatmad.com/gallery/main.php?...chScan&g2_form[formName]=search_SearchBlock&g2_form[searchCriteria]=3c&g2_form[useDefaultSettings]=1)

or a consumer 150 XR2 as per the pics above. Two very different motors though right?!

grandmas denture · 10-02-2012, 12:52 PM

Quote:

Originally Posted by The Docta

There are at least 3 different XR2s right??

Which one is being discussed here. Based on age (late 80's), I assume it could either be a mercury hi-perf XR2 (150hp 2.0 bucket cowl - as used in 3c eg http://boatmad.com/gallery/main.php?...chScan&g2_form[formName]=search_SearchBlock&g2_form[searchCriteria]=3c&g2_form[useDefaultSettings]=1)

or a consumer 150 XR2 as per the pics above. Two very different motors though right?!

... exactly 4 different types xr2 if block design matters
... the last clamshell xr2 150 with hp165 were produced 87
... xr2 becomes race engine 1988 and went to bucket cowl
... dunno exactly if they had hp180 from there or a bit later

... brownband is defo 1984~85

madrat · 10-02-2012, 01:50 PM

Those are handy pics to identify the engine's Chris, Cheers!

Are pistons/rings/bearings easily available for this brown band motor?

driver510 · 10-02-2012, 02:16 PM

You can still get parts for this motor

Renegade · 10-02-2012, 03:31 PM

Aint one of those wanky xr4's Is it?

grandmas denture · 11-02-2012, 01:37 PM

Quote:

Originally Posted by Renegade

Aint one of those wanky xr4's Is it?

... according to cowl its a stock 2.4 200
... haha, i heard a big big secret about those xr4 official explained by a specialist, those xr4 are perfect race engines for small 16ft boats, didnt you know that ?

... cheers for the stripes at the hull