Go Back  Offshoreonly.com > Technical > Do It Yourself, Boating on a Budget
Rebuild or Not? - 502 MPI Leak Down Test Results >

Rebuild or Not? - 502 MPI Leak Down Test Results

Notices

Rebuild or Not? - 502 MPI Leak Down Test Results

Thread Tools
 
Old 09-20-2016 | 07:15 PM
  #1  
Thread Starter
Registered
 
Joined: Jul 2013
Posts: 13
Likes: 0
Default Rebuild or Not? - 502 MPI Leak Down Test Results

Hoping a few people can give me their opinions on my boat. I have a 502 MPI (1993) with 860 hours on it. I had a compression test done which yielded poor results in 3 cylinders. I then took the boat to another mechanic to verify compression and do a leak down test. The leak down test showed that every cylinder was leaking from the intake valve (some more than others). We could not really positively identify any leaking from the crankcase since the valves were leaking badly. I'm on the fence if I should rebuild or put new heads on and run it? I was already thinking of potentially selling the boat before any of this happened, as I wanted to upgrade. Looking for advice on next steps please. The boat is a Formula SR271. I don't want this to become an aging boat that will need more work after I do work on the motor (I.E. outdrive, etc.). Should I sell the boat the way it is, have the heads redone, or a full rebuild?

Just looking to see what others would do. I'm having a hard time making a decision.
Not Today is offline  
Reply
Old 09-20-2016 | 08:59 PM
  #2  
Registered
15 Year Member
 
Joined: Oct 2007
Posts: 8,439
Likes: 94
From: yorkville,il
Default

my advice,pull heads for a valve job and new springs and run it[for a long time].i also would send the injectors for flow testing&cleaning.i used BUP from here for the injector service and recommend him.jmo for whatever it,s worth.
mike tkach is offline  
Reply
Old 09-20-2016 | 09:19 PM
  #3  
Registered
15 Year Member
 
Joined: Jan 2007
Posts: 2,078
Likes: 1,202
From: Murrayville Georgia
Default

I would agree with Mike, you said you are interested in selling it so I would not buy new heads, just have the current ones redone. if the bottom end is sound then you can run it another year or two and sell it with the bonus of being able to tell them that the top end was redone. new heads or rebuilding is money you will never get back when you sell so hold the cost to something reasonable.
compedgemarine is offline  
Reply
Old 10-20-2016 | 08:35 PM
  #4  
Registered
 
Joined: Oct 2012
Posts: 1,332
Likes: 2
From: dfw texas
Default

860 hoursand 15 yrs on orig 502 headgaskets is getting up there and almost good maint on a ole ' 502 . May sway the next buyer yours had the top end refresh ,even if you dont get your money back .
airjunky is offline  
Reply
Old 10-21-2016 | 06:04 AM
  #5  
Registered
15 Year Member
 
Joined: Sep 2008
Posts: 916
Likes: 41
From: Tampa Bay Area Florida/ North Miami Florida
Default

1993 mpi????
Blueabyss is offline  
Reply
Old 10-21-2016 | 06:16 AM
  #6  
SB
Registered
20 Year Member
 
Joined: Nov 2004
Posts: 14,104
Likes: 3,692
From: On A Dirt Floor
Default

Rebuild heads, redo compression and leak down before it goes back in the boat. With heads off you can turn engine over to see the condition of each of the bore walls.

x2 on injectors. Even If they are all tested okay, I'm sure the filter baskets are due to for replacement or cleaning out.
SB is offline  
Reply
Old 10-23-2016 | 02:16 PM
  #7  
Registered
 
Joined: Nov 2015
Posts: 132
Likes: 3
From: tyler tx
Default

Rebuild and enjoy ,,i dont care new or old you will always be tinkering with boat ,,,just my thinking
jdf4068 is offline  
Reply
Old 10-26-2016 | 06:24 AM
  #8  
Registered
 
Joined: Sep 2012
Posts: 523
Likes: 38
From: new baltimore mi
Default

well, if your thinking of selling boat, I doubt whatever money you put in it, you wont get back if your paying to have work done. you may break even if you do the work yourself.
So, having heads freshen up could be selling point...maybe...
its all a gamble...jmo
flashgordon is offline  
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.