Engine starting

[SeaRenity]

I have twins 2005 350 mag horizons w/ MPI. I am following the starting instructions I have been given by the dealer but it seems to me my engines do not start right up. I depress the starter switch half way to start fuel injectors/wait 3-4 seconds then fully depress to start. It turns turns turns then eventually starts. I have even half depressed the switch up to three times ( limited sucess). If the engines are warm they start right up. To compare to my car (also fuel injected) I turn the key and almost instantly start up even after not using the car for over a week. What makes a car so different than my boat engine? Am I doing something wrong? Does anyone else seem to have the same issue?
Thanks
Rich

 

[Lazy Daze]

Battery cables and grounds clean (both at the batteries and where the various cables attach)? What's the condition of the batteries, themselves?

 

[tbirdvet]

I do not believe the injectors start until engine starts to crank and crank sensor tells the PCM when each cyl. is ready for fuel. You may have an erratic sensor of poor fuel pressure.

 

[Southpaw II]

How many hrs. are on these engines? May be time for a new set of plugs.

 

[BonBini]

Not sure what your doing with the switch exercise. Like mentioned above, the fuel injectors only deliver fuel when engine is turning over. Unless your trying to build fuel pressure.

From your description; it does sound as though its taking a long time to fire the cylinders. It could very well be fuel related.

A restricted fuel filter could very easily be causing a delay in fuel pressure building up. As also mentioned above, perhaps a tune up is in order. Filters, plugs, wires....

Having said all that. What seems puzzling is, you describe both engines as doing the same thing! ...Ron

 

[Jimmy Buoy]

I start my engines in the same way, waiting until the fuel pumps cycle off before hitting the starter switch. My thoughts are that there is considerable power used to cycle the two electric pumps so why not wait for the pumps to stop. Then when you hit the starter motor there is more power available to turn those wee beasties over:smt038!

My last boat had good ol' carberated 5.7's that fired up with the first kick of the starter:grin:. Sure, if it had been sitting for a week or so you had to just pump the throttles 3-4 times to squirt some fuel into the carbs, but the result was a VERY quick start (although it would run a bit rough due to a temporary overly rich mixuture:smt013).

When I got my current boat, I was surprised at how much longer it took for the engines to start once being cranked.:smt101 It takes about 5 revolutions to fire and is the same for both engines - hot or cold. The good news is that once started they idle relatively slowly (after the initial surge upon firing) and are VERY smooth. No more 1500 RPM warm-ups before backing off the throttles like with the old engines!:thumbsup:

Like you, I am surprised though that these fuel injected babies done start with the first or second revolution of the engine once the starter is engaged. Maybe the starter motor doesn't spin the engine as fast as my previous 5.7's?:huh:

 

[Stray Cat]

When was the last time you changed those pricey cool fuel filters? I turn my switch on, wait about 5 seconds and they come to life after about a 2 or 3 second crank. They start the same whether they are cold or warm

 

[jwws007]

have you replaced your distributor caps. sounds like you are due, and it really wakes those engines up

 

[SeaRenity]

Thanks for all the responses. To answer the questions: One bank of batteries is new last year (starboard) other bank about two years old --but i don't feel like this is the issue. I have never replaced plugs (I am second owner) engines have about 320 hrs-- I was thinking of replacing this spring.
I have replaced the "pricey" cool fuel filters last spring. No noticeable change in starting. It's not like they don't start-- It just takes four to five revolutions. I still think they should start right up like a auto?
Rich

 

[Lazy Daze]

There's lot's of good suggestions above. Unfortunately, any of them can be right. All I would suggest is to start with the easy/inexpensive stuff.

I've been down the battery cable/connections (at batteries and engine) road before and can definitely say that corroded (it may not look like it until you pull them off) wires/connections can definitely cause this problem. I've even seen wires where they looked good, but the corrosion has actually creeped it's way up underneath the cable's sheath.

This may not be the problem, but it's a good place to start. Worst case scenario.. you've now gone through and cleaned all your connections and grounds and know, for sure, that everything there is happy.

Good luck.

And, yes, since you have MPI (not EFI), it should start like a car (or at least close enough that you wouldn't notice a difference). But, then, this is probably somewhat of a subjective matter.

 

[Redhook98]

4 or 5 revs is about right. When you push the starter swithc halfway, that turns on the fuel pump(s). After they stop, start the motors like normal. What your describing is very very normal. Mine are tuned to the peak of perfection (I am very anal retentive that way), and they start the same way you are describing. Yes, they do start a tad bit qquicker when warmed up already, but then most things do.....