leak down test results on 500hp
 

my 2000 500 hps have 430 hrs on them, so i did a leak down on 1 motor today, keep in mind these have not been run since last september and it is in a non heated garage in pa. i got the garage up to about 60 and bumped motor over a few revolutions and did my test at maintaining 90 psi on the left guage and then took readings on right guage of leak tester with these results. should i be doing a complete refresh or run another year???? or retest after warming motors to temp??

1 5%
8 16%
4 5%
3 15%
6 8%
5 10%
7 12%
2 14%

Thanks rick

When I checked my 575SCi's with 430 hours two years ago,
under the same conditions (not run, cold engines that hadn't been
run in a while) my guideline was to use as gospel the recommendation
right out of the Merc manual of 30% leakdown being the decision point
(and they do specify on a cold engine).

The worst cyllnder port was 33%, the worst starboard was 27%.
I decided to pull and refresh the heads from the port one only that
year. The next year (last winter) I did the second engine.

Everything was in pretty decent shape. As usual the head gaskets used
on the 575SCi suck and that showed, and might have been a factor
in the leakdown. Those are Fel-Pro now. The engine shop, Larry's Engine
and Marine in Tucson, replaced all of the exhaust valves.

I'm not a pro engine builder so take my opinions and experiences with
a grain of salt (I hear a lot of guys say stuff like if it is over 5% and you have over 50 hours pull the engines now and to a total rebuild, or something similarly alarming).

Pesky Varmint

I would do the test warm. If still at the 14-16% range, I'd pull it.


Darrell.

You need to find out where the air is leaking out. Listen and you should be able to hear it. I would also do the test after the engines have been run.

Out carb is intake valves
Out exhaust is exhaust valves
Out valve cover breathers is cylinders

1 5% cranck case
8 16% crank case
4 5% crank case
3 15% ex valve & crank case
6 8% crank case
5 10% crank case
7 12% crank case
2 14% ex valve & crank case

What if i run them to temp by pulling out the impeller and run dry so i dont have to re winterize, also the exhaust manifolds are off the motor i just leaked????

How long should i run them to temp or just get them warm and redo the test.

You need to run them, up to full operating temp. Even better would be to run them in the water under load at least once before doing the test. that will get everything working again, oil back where it needs to be and valves opening and closing like they need to be.

Cold numbers like you have don't mean much unless they are ridiculously high -- then you know you have an issue. But, at your numbers you gotta get things going again to be sure.

If it were me, I'd run another season.

Yea i think im going to fire up the other motor to temp and see what its readings are and if good ill go back to the one i just did and warm it and re check. i would rather pull the engines in like october and refresh the whole things and power up, so if i can run this summer yet i only put 40 hours on a summer it would be best.

thanks i appreciate all your advise

I think on a production engine with those hours, cold, not bad..would bet the majority of leakage in the valves...