2006 4.3L takes two cranks to start

[StaynClassyOnTorchLake]

Im new to boating. I purchased a 2006 Bayliner with a 4.3 Mercruiser in it. It takes two cranks to start 9/10 times. Any ideas what I should replace/adjust.

Seems to run ok after that.

Plugs? Wires? Coil? Carb? What else?

Also I'm interested in upgrading the carb and possible the prop for better performance and higher top end. Any suggestions would be appreciated.

 

[Bondo]

Ayuh,..... Welcome Aboard,..... No, it ain't the coil,......

Which carb ya got now,..?? 2bbl,..??
A 4bbl, 'n intake manifold will net ya 'bout 20 hp more,......

 

[Scott Danforth]

welcome aboard.

first, please explain the steps you go thru when starting the motor.

next, it is almost never the coil....only 3 out of a million coils replaced are ever bad

if you have a 2 barrel carb, you can upgrade to a 4 barrel intake and carb for about 20 more hp. then beyond that, your out of motor. the 4.3 is pretty much near the top of the power output from the factory. if you want better performance and top end, sell the boat you have and buy the boat you want.

 

[Scott Danforth]

Bondo ......we seam to post the same thoughts at the same time often

 

[Bt Doctur]

Im new to boating. I purchased a 2006 Bayliner with a 4.3 Mercruiser in it. It takes two cranks to start 9/10 times.

have no idea what your asking .two cranks to start 9/10 times.
.Can you be more specific abut your problem

 

[Sea Rider]

2 cranks to start seems reasonable, worry if it takes much longer specially when cold cranking..

Happy Boating

 

[tpenfield]

How long is a 'crank' ? If you give a bit more information regarding the time in seconds that the engine cranks before starting, that will be more helpful.

 

[StaynClassyOnTorchLake]

So when I crank it I try for 3 seconds at a time. I've not timed it. Under 5 seconds for sure.

 

[StaynClassyOnTorchLake]

Oh and it has a two barrel carb now and stock prop. I was wondering if I did a progressive pitch prop would give me more top end speed.

 

[Scott Danforth]

as asked prior. please explain every step that you go thru to start the motor in detail for both a cold motor and a warm motor.

 

[Bt Doctur]

with a carb`d motor you have to pump the throttle a few times and set the throttle slightly above the idle setting

 

[tpenfield]

I would not see an issue with cranking an engine for 5+ seconds to get it to fire up. A 3 second 'burst' on the starter may not be enough to wake the engine up

My carb'ed 7.4 Merc would crank for 6-7 seconds before starting . . . but it always did.

 

[tpenfield]

Oh and it has a two barrel carb now and stock prop. I was wondering if I did a progressive pitch prop would give me more top end speed.

Usually the 'stock' prop is the correct prop. So, don't get your hopes up on gaining more speed through prop swaps. Usually the top speed of a boat is more related to the amount of power (HP) rather than the prop.

You can check out the propeller threads in that forum. You will see a lot of trial and error trying out different props. sometimes they send things in the wrong direction.

We are still awaiting the invention of the 'magic prop' that increases power

 

[Maclin]

All things considered, cranking for up to 10 seconds would not overtax anything. Try the throttle manipulations mentioned and crank longer.

 

[jrs_diesel]

Very likely nothing nothing is wrong, other than your cold start procedure.

My neighbor has a 2004 Bayliner with the 4.3L, which has a 2 barrel Mercarb. On his boat for a cold start, we learned to disengage the gearshift so the handle was throttle only. Give it one full pump, all the way to wide open throttle and back to the idle detent (just forward of the neutral point).

This does two things on a Mercarb. One, it sets the choke for a cold start. Two, the accelerator pump on the carb squirts a small shot of fuel into the intake to help start the engine.

Once you do that, crank the engine and it should fire and start within a few seconds on the first try. Leaving the throttle handle in the throttle only setting allows you to high idle the engine to help warm up and keep a cold engine running. Marine carbs do not have an automatic high idle feature like cars do.

The choke on a Mercarb will automatically open up within a couple minutes. A warm engine should start right up, no throttle pumping required.

 

[harringtondav]

Observation about changing carbs: My '96 4.3LX has the Weber 4 bbl 180 hp.. Two years later my wife's tribe bought a new boat with the same 4.3LX but it came with the 2bbl Mercarb. 190 hp. Your 2006 has the 4.3 Vortec, and I believe the higher hp. models are EFI. I'm guessing you have all the hp. you are going to get unless you go with a big CFM 4 bbl. carb. But I think Merc. would have done that if they believed the 4.3 could survive.

The fuel injected 4.3 has a knock sensor that tells the engine controller when to back off the juice and timing before the engine is damaged.

 

[jrs_diesel]

The 4.3 with the 2 barrel Mercarb and Vortec heads was 190 HP.

The 4.3 with the 4 barrel Weber and Vortec heads was 205 HP.

The 4.3 with EFI was also 205 HP.

Vortec heads came in around 1996.

 

[harringtondav]

The 4.3 with the 4 barrel Weber and Vortec heads was 205 HP..

Thanks. I participate to contribute and learn. Maybe I'll research the Weber/eEdelbrock jet sizes available. ...but probably not. My 174 Larson 180 hp comes close to chine walking at 52 mph now in glass. I want to be around long enough to see grand children.

 

[StaynClassyOnTorchLake]

It does seem to start better if I give it a pump and some throttle defore I turn the key. I just wasn't sure if it should start any easier than that, or if pumping and some throttle was just compensating for some other underlying problem that needed attention.

I've had it out a couple of times and ran wide open for a few minutes. The speedo says I'm doing about 50. That's pretty fast.

Are the 4.3 motors known for being sturdy and reliable? Should I not run it full throttle? Obviously the harder I run it the more of a chance there is to break something. I'm not new to motors, but I am new to this motor. I just am not sure on how taxing it is to run it so fast. I don't want to break it, but I do like to go fast when it's glassy, so it's hard to not push it that extra inch of the throlle to top it out.

Should I never go wide open for too long, or is wide open no big deal if the motor has problem fluids and is cooling properly?

I guess I just don't know enough about the motor to know what's ok and not really ok. Like I said, Indont want to break it or over tax it, but it is fun to rip across the lake.

Thanks again for your replies.

 

[tpenfield]

How often do you run your car engine at WOT and for how long?

You can run at WOT on your boat occasionally but I would not run it like that for more than a minute or two . . . nothing good can happen to the engine beyond that. Run at about 80% throttle if you want to go fast.