OBX

I have a 1994 24' Baja Outlaw with its original Mercruiser 7.4L 300 hp carburetor engine. I bought this boat used 3 years ago with 149 hours on it. (It now has 239 hours.)

In the 3 years I've owned it, it's always been very difficult to start when the engine is cold. It usually takes 15 to 20 cranks of the engine coupled with pumping the throttle about 2 dozen times before it will start. (And sometimes the amount of throttle pumping doesn't even seem to make a difference.) Once started, it runs great, and subsequent warm starts during a day of boating are NO trouble (usually requiring no throttle pumping at all).

My mechanic has not been able to help with the starting problem. He has confirmed the gasoline is not leaking down from the carburetor. He has replaced both the fuel pump and the anit-siphon valve. Neither has helped to improve the starting.

The engine hasn't failed to start for me, yet (knock on wood), but I'm probably killing my starter in the process. Does anyone have any idea of what might be wrong and what I can try next?

Thanks!
Mike

excaleagle42

i assume you have a quadrajet with electric choke? the choke is closed when cold and is still hard to start? you could try a couple pumps of the throttle after you prop the choke butterfly wide open by the linkage with a tie wrap or electrical tape, and open your throttle up at least half way while starting. you should be able to see into the intake when you look down the carb throat with a flashlight before you start the engine. if it fires right off you will obviously have to pull back on the throttle quickly, but chances are your leaking fuel and your in need of a rebuild. or your idle adjustment screws were overtightened at some point in time and may have broken a tip and your in need of a rebuild. good luck.

OBX

Thanks for your reply, excaleagle42.

My mechanic did take the carburetor off of my boat, put it on his workbench, and left it there for a day to check for gasoline leaking down. I wasn't there, obviously, but he did say there was no leaking.

Regarding the idle adjustment screws, is it possible they were overtightened and something broke yet it could still be idling okay (because it is)?

Is it easy to tell if I do have the quadrajet with electric choke carb.?

Thanks!
Mike

blown formula

Mike, I had a '93 w/454-300 also. It did exactly the same thing yours does, except after it was started, it would start every consequtively(sp?) day. if a week or more were in between starts back to the same problem.

My fix was to install a new 454-450hp & pro-charger, never a problem after that!!!

Seriously, install an electric fuel pump and regulator and problem will be solved.

ragtop409

No a 1994 has the Weber (edelbroc carter) carb but it does have an electric choke. You can ajust them fairly easy I did this and it made my 95 330 hp 7.4L bravo start much easer when it had been seating. Charlie

Vinny P

This should be a simple problem to fix. But, you need to see the boat to fix it properly. Probably a choke problem. Sounds to me like you need a new mechanic. This should not be hard to diagnose if you know what you are looking at.. Your idle mixture adjuster screws have nothing to do with a hard cold start problem. These screws only control the idle mixture.

excaleagle42

obx
webers have two floats in them. i would check them and play with the choke adjustment like ragtop said. i like blown formulas first suggestion best though.

excaleagle42

Your idle mixture adjuster screws have nothing to do with a hard cold start problem. These screws only control the idle mixture.

checkmate, this is right from the edelbrock carb manual.
"Fuel is drawn through the Idle System by the intake manifold vacuum that is communicated at the Idle Screw Port and Transfer Slot. The emulisified air is then drawn through the restriction, a drilled passage that serves to incresae the velocity of the air and fuel and promote better mixing. The Idle Screw Port is a variable discharge restriction that is adjusted by the engine tuner to achieve the desired A/F ratio at engine idle.

Vinny P

excaleagle42;

I am not quite sure as to whether you are disagreeing with me or maybe I am not reading your reply to my comment about the idle mixture screws correctly. But, didn't Edelbrock say the same thing that I said?? They just wrote more extensively that the idle mixture screws adjust idle mixture, which comes after the initial start-up.

formula31

How about "no accelerator pump shot" did you check to make sure the accerator pump is squirting gas when you pump the throttle after a sit? Just a thought.