Reply
 
Thread Tools Search this Thread Display Modes
 
Old 01-03-2011, 02:29 AM   #1
Lt. JG

 
Join Date: Jan 2011
Location: Brisbane, Australia
Posts: 46
Default 5.0L wont start

Hi All

Last had the boat out 3 weeks ago and ran like a dream. Has been raining since then and havent been able to get out. boat is outside but covered.

Yesterday, drove 60 miles to put it in the water, and couldnt get it started. Thought it might have been just flooded, but an hour later, and I was loading it back on the trailer with no luck. Also tried again this morning and no go.

Boat turns over, but doesnt seem to fire. occasionally fires as though it is going to start, but then nothing. When ignition is let off, it also has some blow back through the carby, which I thought may be something to do with the timing?

I also went and had a better look this morning, had key on while looking at the plugs, and all of a sudden alarm started going, and would not stop. When cranked over alarm stops, and then starts again afterwards. Motor Oil is constantly checked, and is just below full.


Had the boat fully serviced and checked over a month ago, everything looks healthy, plugs are clean.

I have just finished reading this post
http://www.maxumownersclub.com/forum...ght=boat+start

Towards the bottom of the post, someone mentions could be oil sender or kill switch. I would be leaning towards one of these being the problems, but does anyone else have any ideas, or can help diagnose and fix the problem before I take it to a mechanic?

Boat is a 1999, 1900SR, 5.0L carby.


Thanks
__________________

johno270583 is offline   Reply With Quote
Old 01-03-2011, 01:41 PM   #2
Admiral

 
ss3964spd's Avatar
 
Join Date: Jul 2009
Location: Fairfax Va
Posts: 1,512
Send a message via Yahoo to ss3964spd
Default

Ya need 3 basic things for the engine to start: fuel, compression, and ignition. Fuel; remove air cleaner/spark arrestor from top of carb, look into the top of the carb while opening the throttle (an assistant, or really long arms, helps). If you see gas being squirted into the carb you can check "fuel" off your list. Compression; barring a catastrophic failure compression does not just go away so check that off your list too. Ignition; pull the spark plug wire from any one of the plugs, pull the boot back until the metal connector is close the boot opening, position the metal connecter close to a grounded metal part of the engine - about 1/8 to 1/4 of an inch (needed to suggest holding the plug wire boot with something insulated), and have someone try to start the engine. No spark = no start.

Yes, the engine probably has a safety circuit that disables the ignition if it senses a lack of oil pressure. The oil pressure sender is the device, and is inexpensive to replace. I believe you can validate it by jumping the two wires that connect to the sender. If place a jumper (like a paper clip) across the wires and the engine then starts - well, there ya go. If not, you'll have to dig in deeper.

Dan
__________________

ss3964spd is offline   Reply With Quote
Old 01-04-2011, 06:03 AM   #3
Lt. JG

 
Join Date: Jan 2011
Location: Brisbane, Australia
Posts: 46
Default

Thanks Dan

More than enough fuel floating around the other day, so dont think that was a problem (also forgot to mention I tried using some 'Start ya Bastard', or Ether the other day, didnt help), which leaves the spark. Will check the Plug lead as you mentioned, then oil pressure sender also as you have mentioned and let you know how it goes.

Thanks again
johno270583 is offline   Reply With Quote
Old 01-04-2011, 02:05 PM   #4
Admiral

 
ss3964spd's Avatar
 
Join Date: Jul 2009
Location: Fairfax Va
Posts: 1,512
Send a message via Yahoo to ss3964spd
Default

No problem John.

If you have a product available that is actually called "Start ya Bastard" I'm moving to Australia because, apparently, you blokes have a sense of humor.

At this point you'll also have to keep in mind that, if you've been cranking and cranking the engine - thereby dumping lots of fuel into the cylinders, the spark plugs might now be fouled beyond use. Might be a good idea to remove at least one to have a look. If it looks wet and icky - consider replacing 'em all.

Dan
ss3964spd is offline   Reply With Quote
Old 01-04-2011, 08:54 PM   #5
Moderator

 
Join Date: Apr 2008
Posts: 3,555
Default

SS, you're always a wealth of knowledge. I always thought the 3-part equation was Fuel, Air, Ignition . Obviously that would apply to any combustion. Certainly an engine will need compression too, but wouldn't that make it a 4-part equation?

On a side note: Would the engine still turn-over when the kill switch is engaged? I thought it would just 'click'. IF so, couldn't we rule out the kill switch from the equation?
__________________
Leave me alone, it's Boating Season!!!
shrew is offline   Reply With Quote
Old 01-04-2011, 10:23 PM   #6
Admiral

 
seapuppy's Avatar
 
Join Date: Nov 2005
Location: Everett Wa
Posts: 4,681
Default

the engine will turn over fully if the kill switch is engaged...(don't ask how I know.)...but it just wont fire....

SP
__________________
Don't compare your life to others. You have no idea what their journey is all about.
------------------------
SSN683 Association member
Par Excellence
------------------------------
2008 Bayliner 340 - "Wild Whim"
--------------------------------------
I live in my own little world....but it's okay-they know me here!!!

Avid practitioner of the martial art: KLIK-PAO.
Tap-Rack-Bang

Anyone that sez "Size doesn't matter" has never owned a boat!
seapuppy is offline   Reply With Quote
Old 01-05-2011, 01:23 PM   #7
Admiral

 
ss3964spd's Avatar
 
Join Date: Jul 2009
Location: Fairfax Va
Posts: 1,512
Send a message via Yahoo to ss3964spd
Default

Shrew,

My dear wife once said to me, in her sweet, loving way; "...there's more than a passing possibility that you're wrong.....". Her timing and delivery were perfect, I laughed for an hour.

I consider "fuel" to be the combination of air and gasoline, since a gasoline engine won't run without both present. (insert wife's comment here).

The kill switch is certainly a possibility, and would easily explain why it was running fine and now it isn't. All the rain/moisture might also explain it - perhaps enough moisture collected under the dist cap to kill it.

Dan
ss3964spd is offline   Reply With Quote
Old 01-05-2011, 04:16 PM   #8
Moderator

 
Join Date: Apr 2008
Posts: 3,555
Default

LMAO!!!!! Very good.
__________________
Leave me alone, it's Boating Season!!!
shrew is offline   Reply With Quote
Old 01-21-2011, 09:51 AM   #9
Lt. JG

 
Join Date: Jan 2011
Location: Brisbane, Australia
Posts: 46
Default

Ok, replaced both switches and sender, just to cover all bases, and I am about to go on a bit of a rant here.

Before I go further, I should mention that at no point while working on the motor recently, have I heard the Fuel pump running while the ignition is in 'ON" position. Should it be running when ignition is turned to 'ON'?

The reason I ask this, is because after replacing the switches and reconnecting, the fuel pump was still silent. After replacing each switch, I turned the engine (briefly) with a timing light connected, to see if it would flash when turning motor over, showing I was getting spark. NOt sure if I didnt have things connected well enough, but I decided to look further into it.

In the end, I took the purple and purple/yellow wires off switch on lower back of motor, port side (is listed as one of the starting and charging components in Mercruiser manual), and joined them together. Immediately fuel pump started running. First attempt at starting the motor, and hey presto! Started!!

I immediately assumed there is some problem with the switch, however I have since pulled apart the old one, and figured out exactly how it works (oil pressure pushes the 'gate' which completes the circuit).

SO after all that, and now I am home and have had time to think about it, a couple of questions:

1. is there a problem with the new switch, should fuel pump be running when ignition turned to 'ON'?

2. If not, have I just assumed that there is something wrong with switch when it is ok (I will actually try to start it when all connected next time!), or is there something else that I am overlooking?


And, for all those disbelievers, I have attached a photo of 'Start ya Bastard' ether.
Attached Images
File Type: jpg photo.jpg (130.1 KB, 18 views)
johno270583 is offline   Reply With Quote
Old 01-21-2011, 12:10 PM   #10
Captain
 
Join Date: Sep 2009
Location: Almere, Netherlands
Posts: 710
Default

john,

if you think the fuel pump is the problem take the hose of the fuelpump that connects it to the carburator......turn the key on like you are starting the motor, fuel will come out of the hose or it wont......you also can install a little fuel can on the hose that leads to the carborator and try to start the motor (bypass) dont forget to temporary disconnect the fuel pump.

just a simple option to get to know if the problem is befor or after the fuel pump.....but every time i turn my key one click to the right i hear the sound of the fuel pump that tells me its coming on pressure to transport the fuel....if you dont hear that anymore........??????

succes, and greatz, ed
__________________

ed & inge is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 10:16 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.