Why won't my boat start again?! It ran great once started last week (previous post)

Momsboat

Cadet
Joined
Sep 3, 2011
Messages
25
Arrgghh...after weeks of frustration, we finally got our mercruiser 3.0L, 4 cyl. to start last week. We started it, shut it down, started it again, then let it run on the muffs to temperature, shut it off, started it up again. Waited a couple hours, checked again, and it again started up. Of course, the weather had turned bad, so we buttoned it up and parked it. (reference previous post) More bad weather, work, etc., and no chance til now to try again. Planning fathers day on the lake tomorrow - thought we better just give it a quick check today so we can get an early start to the lake, and...you guessed it; it won't start!

When it was running last week, checked timing, etc., and it purred like a kitten. Never expected it wouldn't start today - don't know what to do! Side note - we never really did figure out what we did that finally got it to start last week..guess we didn't really solved the problem. But don't know where to go.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
Re: Why won't my boat start again?! It ran great once started last week (previous pos

What vintage?
 

Momsboat

Cadet
Joined
Sep 3, 2011
Messages
25
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Oops....sorry - it's an 88 sea ray seville 20br.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Starting procedure can often make a big difference in how well a motor starts.

Turn on the bigle blower to remove any fumes.

Open the engine cover an give it the 'sniff' test just to be sure, then close the cover.

Push in the 'Neutral only' button at the pivot point of the Control Arm and move the arm forward to WOT and back to almost straight up. You want to stay in Neutral only so don't bring it back to straight up or the button will pop out.

Now slowly move the arm forward until you feel it begin to open the throttle, you want the throttle open just a hair.

Double check that the kill lanyard clip is attached, (if equipped).

Crank the motor.
 
Joined
Jun 17, 2012
Messages
940
Re: Why won't my boat start again?! It ran great once started last week (previous pos

I don't know what was covered in your previous post, but from your description of the problem I would suspect either a moisture/condensation problem ( cap, wires) from that bad weather, OR a choke problem.
 
Joined
Mar 27, 2010
Messages
3,008
Re: Why won't my boat start again?! It ran great once started last week (previous pos

On some Rochester carbs, after long periods of non use, the welch plugs in the carb can slowly leak into the engine and empty the fuel bowl. Then when you try to start you have a difficult time until the carb has fuel again.

Not saying this is your issue but it does happen to some.
 

Momsboat

Cadet
Joined
Sep 3, 2011
Messages
25
Re: Why won't my boat start again?! It ran great once started last week (previous pos

How do I check if the choke is sticking or something? We've been over the cap, points and wires pretty good.
 
Last edited:

ktbarrentine

Lieutenant
Joined
Dec 12, 2011
Messages
1,296
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Look into the carb with engine cold. Choke plate should be closed (with a very small gap) after one pump of the throttle (sets the choke). Then slowly opens as engine comes up to temp after starting (non-electric choke).
My choke was stuck hard (frozen) open when I first bought my used 1990 5.0L . The PO just lived with it, although it made starting the engine very hard when cold. Overhauled the carb, set the choke, all is well.
 

LagunaBlue

Seaman Apprentice
Joined
May 29, 2013
Messages
33
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Hi,

What exactly happens when you turn the key? Does the motor turn over or does the starter just click? What is the condition of the fuel and spark plugs? Have you checked all grounds for clean and tight connections?

Lets narrow it down by engine system and go from there :joyous:

-Mark
 

Momsboat

Cadet
Joined
Sep 3, 2011
Messages
25
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Thanks mike. it cranks strong. Just never gets that burst to start. We have checked fuel going into carb - good. Replaced plugs and wires last fall. Was put up for winter with fresh gas, treated. We spent three weeks trouble shooting, but haven't found anything not checking out. it did start, but not sure what we did that changed. Once started last week, it ran great. Losing our minds!!
 

LagunaBlue

Seaman Apprentice
Joined
May 29, 2013
Messages
33
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Thanks mike. it cranks strong. Just never gets that burst to start. We have checked fuel going into carb - good. Replaced plugs and wires last fall. Was put up for winter with fresh gas, treated. We spent three weeks trouble shooting, but haven't found anything not checking out. it did start, but not sure what we did that changed. Once started last week, it ran great. Losing our minds!!

Are you getting spark in each cylinder? Pull the cap and check for cracks. Also look for corrosion on the rotor & inside the cap terminals. What year is your engine? Do you have EST or standard ignition?. Check your coil or ignition module depending on what you have.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Re: Why won't my boat start again?! It ran great once started last week (previous pos

Do you get a strong spark from the coil wire? Pull the center wire from the distributor and position it near (1/4 inch or so) bare metal. Turn er over. Should get a strong blue spark. If not look to the points (if so equipped).
 
Top