Why Won't My Boat Turnover When Launching the Boat??

[Deeznuts 0]

Every time I take my '99 ski centurion D-Drive out to the launch, it takes forever for it to turn over, and a couple of times I ended up flooding it! Is it because it has sat for like 1-2 weeks, or is it the steep angle of the ramp causing it to do something to a gas line?  IDK... Anyone with the same or similar boat have this issue? Thereafter, the boat runs good for the day and starts up fast each time.

[volzalum 280]

Do you mean it takes a long time to start (i.e., the engine is turning over but it doesn't start)? Or do you mean the starter is not turning the engine over?

If turning over and not starting, it could be several things from plugs to vacuum leak, etc. What Engine is in your boat?

If not turning over, check your batteries and starter.

[Deeznuts 0]

First it sounds like it's trying to turn over, like it keeps cranking and cranking(like the sound of trying to start an old muscle car). This is after I have either not initially pumped the throttle before starting it, or pumped the throttle once in neutral. My friend has the same boat, and he said "give it two pumps of the throttle before starting it"! So that doesn't work! Then other times I don't pump the throttle at all before initially trying to start it. Either way doesn't start it, but it keeps cranking trying to turn over. Then after all that nonsense, it will act like it's going to turn over, and turn on for a moment, then die. So then I crank it again, and it's turning on, but sounding like it wants to die(like someone coughing something out), so I try to rev it in neutral, and it still dies. Then after a couple of tries of that, I end up flooding it, then it smells like gas. So then I wait a moment, and try like two more cranks of the engine, then it starts! It's kind of embarrassing at the ramp, cuz there's guys around me looking. lol

[Jlagos 23]

Do you have your boat at home? Start it on your driveway (with water i.e. fake- lake attached so you don't ruin the impeller) the night prior or first thing in the AM. Sounds like your carbureted. The last carbureted boat I had was the same as your friend. 2 often 3 pumps prior to turning the key to crank the engine. It typically started quickly. If not, I would move the throttle to a position that would rev the engine to about 2000 rpm and then crank (turn over) the engine. It would fire up (turn on) at that time. Like volazulum said make sure the batteries are in good shape to allow a good quick crank (turnover) as it requires the cylinders moving to pull gas in via the carburetor. Sometimes the position of the boat will affect some boats. If sitting for an extended time it will cause the gas to dissipate from the carburetor. Do you the carb needs cleaning/rebuilding. When you turn on the ignition and the electricity is sent to the dash board (such as when the dummy lights turn on in the car dashboard) do you here the fuel pump cycling/humming briefly. 

[Deeznuts 0]

The boat is stored on flat ground(the street). I will try to tighten all the hoses before our next outing, and see if that makes a difference at the launch. If not, then it must be a carburetor issue, cuz I have two batteries that I'm running, that show the right amount of voltage. I'll also try 3 cranks before turning the key on, and see if that makes a difference. I bought it this last March from a guy who knew nothing about boats, haha, and had almost everything replaced or fixed on the boat! I bought it for $13K, which was a steal, cuz he had all the interior and upholstery redone, new tower with full sound system, new impeller and engine worked on, whole new prop and assembly, etc etc. He put more moneyinto the boat than it's value...it was like getting a new boat!   

[TexP51 6]

Never fun problems.  Here are some diagnostic suggestions if you have a OE Mercruiser ignition & fuel system: W/ hard start and believe engine is in normal wear condition.  Emphasize just hard start, as you didn’t mention rough running, backfire or spitting through carb.  

1) Replace fuel filter. Test.  Perfect world, also test fuel pressure to see if you have a weak fuel pump. 

2) I’d suggest you unclip the distributor cap & check the 8 contacts inside for corrosion, & same for the rotor - if so replace.  Test. 

3) Next, pull one spark plug & look for 1 of 3 conditions on the electrode end - that will look like dusty brown, dark burnt charcoal or, oil covered.  You want the dusty brown look.  The dark charcoal look is rich mixture - that commonly could be caused by carb issues, or ignition timing is off.  If oil covered replace all 8 plugs. Now need to TIME the electronic ignition.

4)  If you can get the engine started you can time the engine.  It has to be running @ 1800 rpm. Borrow/rent a Inductive timing light & adjust the distributor to set timing to proper position.  Make sure to use #1 spark plug wire for the timing pickup.  The timing Instruction for Mercruiser Thunderboly electronic ignition systems is on the web - make sure to follow instructions as you need to use a jumper wire to connect to the ‘ignition system timing lead’ (PUR/WHT wire) to a good engine ground (-). This locks the electronic ignition module into the “Base Timing Mode”. - using the timing light to look at the timing mark on the crank & line up w/ v-indicator on timing chain housing indicator.  Loosen distributor to adjust & then lock it back down.  Test.

5) If those don’t improve your hard start - find shop to overhaul carb, or buy rebuilt or new one.  You can do OH yourself if comfortable, but recommend left to pros.

Good luck.
 

[Deeznuts 0]

Tex: Wow!!  Thank you for all that instruct and info!! Extremely helpful!! I'll get my boat friend to help me...