Go Back   Maxum Boat Owners Club - Forum > Maxum General > Engines
Click Here to Login
Register FAQ Community Calendar Today's Posts Log in

Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-30-2020, 05:01 PM   #1
Lt. JG
 
Maxum1800MX's Avatar
 
Join Date: Apr 2018
Location: Vancouver, BC, Canada
Posts: 22
Default Engine stalling in idle or low rpm (solved)

Now I know how a blown manifold gasket sounds like 🧐

I know there could be a 100 reasons why your boat is stalling in low gear but after checking the fuel pump, fuel lines and filters, spark plugs, distributor cap, rotor, engine timing, throttle cables alignment and rebuilding the carburetor the tiny little fumes on top of the engine gave it away. I wasn't sure if it was just some oil/dirt residues fuming but when I sprayed some water on it I saw tiny air bubbles coming straight out of the gasket. Funny part is, this gasket is only 2 years old. Hope this helps someone out there 🤓
Attached Thumbnails
manifold_gasket_blown.jpg  
__________________

__________________
________________________
Maxum 1800 MX
Maxum1800MX is offline   Reply With Quote
Old 07-30-2020, 05:08 PM   #2
Lt. JG
 
Maxum1800MX's Avatar
 
Join Date: Apr 2018
Location: Vancouver, BC, Canada
Posts: 22
Default

If anyone has some ideas why this manifold gasket would get blown after only 2 years please share. I suspect reach fuel - the spark plugs were black (replaced last season). I've rebuilt the carburetor, adjusted the air/fuel mixture needle and installed new spark plugs and distributor cap/rotor. Engine temp was always good. I'm also switching to high octane 94, no methane gasoline from now on.
__________________

__________________
________________________
Maxum 1800 MX
Maxum1800MX is offline   Reply With Quote
Old 07-30-2020, 06:21 PM   #3
Admiral
 
mmwjr's Avatar
 
Join Date: Feb 2012
Location: Essex, Maryland
Posts: 10,587
Default

Not sure why an exhaust leak would cause the engine to stall but the failed gasket may have caused a leak all the way to one of those intake ports and that will cause issues.
__________________
1997 Silverton 362, 7.4 Crusaders
1997 2400 SCR, 5.7 Vortec / Bravo 2

Mike
mmwjr is offline   Reply With Quote
Old 07-30-2020, 09:03 PM   #4
Captain
 
jrsick's Avatar
 
Join Date: Oct 2011
Location: Chesapeake, VA
Posts: 556
Default

Do you have a machinist ruler to check flatness on mating surfaces?
Black plugs may have been oil vice gas.
jrsick is offline   Reply With Quote
Old 07-30-2020, 11:50 PM   #5
Lt. JG
 
Maxum1800MX's Avatar
 
Join Date: Apr 2018
Location: Vancouver, BC, Canada
Posts: 22
Default

Both, the engine block and manifold don't have straight surfaces, especially around the exhaust openings. I'll have to take it to a machine shop in the winter.
__________________
________________________
Maxum 1800 MX
Maxum1800MX is offline   Reply With Quote
Old 07-31-2020, 11:43 AM   #6
Captain
 
jrsick's Avatar
 
Join Date: Oct 2011
Location: Chesapeake, VA
Posts: 556
Default

Hopefully a good fit between intake and head will fix your problem.
Do the plugs smell like gas? I ask because I think an intake leak would result in a lean condition, not rich.
__________________

jrsick is offline   Reply With Quote
Reply

Tags
gasket, low rpm, manifold, mercruiser 3.0l, stalling


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 Off
Pingbacks are Off
Refbacks are Off


Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 02:31 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.