Reply
 
Thread Tools Search this Thread
 
Old 07 August 2016, 18:38   #1
Member
 
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 649
Mercury 15hp oil/fuel problem

Not my boat, but friend has a Mercury 15hp 4-stroke twin cylinder Big Foot - I don't know the year.
Recently started to cut out at idle but OK at wider throttle openings. Fine before that. Oil level also around 1/2" to 3/4" higher than than it was when he last checked it before this issue. No water in oil & (to my surprise) no particular smell of petrol in the oil or obvious thinning of the oil.
My own suspicions would be a perforated fuel pump diaprhagm, sticky float valve or leaking carb float.
Any known issues with these engines in this department?
__________________

__________________
paintman is offline   Reply With Quote
Old 09 August 2016, 15:15   #2
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
A buddy of mine had his fuel line disintegrate from the inside; it was apparently some sort of plastic lined rubber hose. Any evidence of contamination in the filters or fittings? Unlikely, but something to look at.

Also check that the primer bulb firms up when pumped; if it doesn't, a small leak in the line may be the issue.

Carb cleaning and rebuild (with appropriate replacements) is always a good thing.

jky
__________________

__________________
jyasaki is offline   Reply With Quote
Old 09 August 2016, 15:43   #3
Member
 
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Mercury
Length: 3m +
Engine: Suzuki Outboard/25/4
MMSI: 235074042
Join Date: Oct 2011
Posts: 3,214
So the engine oil has increased by 50 - 75%? I would drain the oil completely before anything, oil will float on top of petrol & water unless that's what you have done but very strange
__________________
jeffstevens763@g is offline   Reply With Quote
Old 09 August 2016, 18:07   #4
Member
 
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 649
Thanks for the replies. His mechanical ability is fairly limited so he's decided to get it looked at by one of the local outboard specialists.
Hopefully that will be in the immediate future & I'll post the result when & if I find out!
__________________
paintman is offline   Reply With Quote
Old 10 August 2016, 11:52   #5
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,604
RIBase
Quote:
Originally Posted by jeffstevens763@g View Post
oil will float on top of petrol
No it won't, it'll just thin the oil.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 10 August 2016, 12:00   #6
Member
 
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Mercury
Length: 3m +
Engine: Suzuki Outboard/25/4
MMSI: 235074042
Join Date: Oct 2011
Posts: 3,214
Quote:
Originally Posted by Nos4r2 View Post
No it won't, it'll just thin the oil.
Yep got that wrong way round oil & petrol will float on water cheers nos
__________________
jeffstevens763@g is offline   Reply With Quote
Old 21 August 2016, 03:49   #7
Member
 
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 649
Problem solved.
Diaprhagm - part no 9 in the attached - had failed & petrol was passing down a couple of the bolts - part nos 8 - and into the oil.
Diaprhagm - part 4 - was fine & is being kept as a spare as the repairer managed to track down a pump overhaul kit.
Mercury Marine 15 HP (4-Stroke) Fuel Pump Parts
__________________

__________________
paintman is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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




Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 23:56.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.