Leak Down Test
 

Ok, Iam Looking At A Boat W/ 500efi With Only 14 Hours. I Had A Comp. Test Done 150-152 Across The Board. Good. The Leak Down Was 18%on The Low Side And 26% The Highest. The Boat Has Been Sitting-up Around 6 Months. What Do You Guys Think. Also The Motors Are 2002. Thanks In Advance.

Re: Leak Down Test
 

18 TO 26 PERCENT IS NOT THE GREATEST CONDITION FOR A LEAK DOWN YOU MAY WANT TO RESEARCH THAT A BIT FURTHER TO SEE WERE THE LEAK IS GOING IF ITS PAST THE VALVES ITS NOT TO BAD A VALVE JOB WILL MOST LIKELY FIX IT BUT IT MAY BE FURTHER INVOLVED.HOPE THIS SHINES A LIGHT LAZ MESA WWW.MESABALANCING.COM

Re: Leak Down Test
 

That is bad leakdown for a motor only having 14 hrs on it. Last winter I did leak down on a motor that I run on the edge of detonation with 10+ lbs of boost & worse was 15% after 100 hrs.

Re: Leak Down Test
 

I see all kinds of red flags on this one. I wouldn't expect to see 26% on that motor after 240 hours.

Re: Leak Down Test
 

I Think It Is Due To The Time The Boat Has Set-up. Could Rust Have Got On The Values And Caused The Values Not To Seal. And Would Running The Boat Blow The Rust Out And Fix The Seal Issue.

Re: Leak Down Test
 

i was always told a cold leakdown test is a 1/2 step above useless. The engeinmust be at or close to operatign temperature so everything will seal right and not leak.

Re: Leak Down Test
 

anybody else..............................thanks

Re: Leak Down Test
 

I agree, change the oil and filter first, put some time on the motors under load and then recheck the leakdowns on warm motors. If its just a little valve seat rust it will probably improve a lot. If it does not then squirt a little oil carefully in each cylinder and retest. If it then improves a moderate amount you've probably got ring issues and if it is still higher than 15%, you've got a major rebuild in order and the boat should price accordingly.
Raylar

Re: Leak Down Test
 

Leak down the engine while still warm.

Re: Leak Down Test
 

yes, the leak down was done when the motors were cold............also the compression test was from 150-160. its hard to see why there would be a issue with the motors with only 14 hours.

Re: Leak Down Test
 

I go out on a limb here. We make leak testers and sell a few hundred a year. For represenative numbers on the engine, as Info said, you need to leak the engines after they have reached operating temperature. This allows the metal parts to expand due to the thermal temp. With that said, now out to the limb, with the "new thinking" on ring gaps and "loose" clearances that have been experimented with successfully in motorsports, it has been a growing trend to not pay to much attention to leak numbers partly due to the fact that the test is not done in real life conditions. Kinda like sitting in a car, not driving it, and saying damn, this thing handles good. I'm not saying throw them our or don't do them, but with nice even compression numbers like these engines have, it would be my guess to venture a little carbon build up, we all know these things run rich, has to do with the leak numbers.

Chris

Re: Leak Down Test
 

Chris-- You make excellent points as usual. You'd obviously expect uniform compression numbers from an engine with 14 hours. What's an acceptable Leak Down number in a recreational marine engine is certainly different then ,let's say an engine used for drag racing. My only point is that a prospective boat buyer looking at a motor with 14 hours and an LD of 26% on any cylinder should certainly understand what's driving that value before committing to the boat. Good dialogue as usual--Lou

Re: Leak Down Test
 

Scott
Good work on your part to have the tests done. Now, place your wallet back in your pocket and slowly back away from the boat.