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Need some help and thoughts!

222Coblat

New member
Hi all,
I'm new here, can't even spell my name right lol. I have a 1994 Cobalt 222 with a Mercruiser 5.7 carbed motor. I bought this boat 3 years ago, its my third boat, should be the nicest one I've owned, but has overall been a headache. It always tended to start a little hard, and it seems the more money I throw at it, the bigger the problem gets. At this point, I have had the carb rebuilt twice, new plugs, wires, cap, rotor, fuel pump was replaced right before I bought it, and I have a receipt for that. All work was done by a professional boat shop with a good rep. Also, had the impeller changed, the manifolds, risers, and gaskets. It will be going back into the shop in a couple weeks, as the last time I had it out, it would move fine at lower RPM's, then it would start slipping/over rev when I tried to increase throttle. I'm HOPING the rubber busing I hear about near the propeller just rotted out or broke, as the prop did hit some sandy bottom right before this issue happened. However, my main question is, I can usually start it relatively easy in the driveway on earmuffs, but if I go to the gas station and then home, or towing it out to use it at the lake, it seems like it makes it REALLY hard start after moving around. I had the gas checked, no water in the fuel water separator, gas is fresh, just seems like if its been sitting it will start easy, but after moving/towing it around it wants to hard start like its out of gas. It cranks away, then crank,crank,crank like it almost catches and wants to start, then finally starts. Once its running it tends to run good other than the recent RPM/slip issue, but I have had all the parts I could think of replaced to help with this starting issue, as I hate sitting on the ramp for a couple minutes cranking trying to get the engine going. Two boat shops told me its just how the boat is, but my previous 1992 Bayliner with a 305 that was carbed started like a champ, no issues like this at all. I'm ready to sell this and get a fuel injected boat, but with kids and finances being what they are, I'd really just need to keep this one if I can get the problem figured out. Can you add an electric fuel pump to replace the mechanical one? Would that potentially help solve the hard start issue, as it seems like its acting like its out of gas before it starts? Even after its started and ran around, once I park it and go to start again a little later, it hard starts again....any ideas let me know, thanks in advance for any help or suggestions.
 
2X on the Welcome.

is the choke set properly? is there fuel in the float bowl when you get to the ramp?

I don't think the moving has anything to do with it unless there's another problem that the moving just makes worse.

you can always remove the mechanical pump and wire up an electric one.....but you'll be better off diagnosis the issue vs throw more money into parts...
 
This is a common problem with carbed boat engines, and especially since that damn ethanol gas came about. Sitting there in a hot bilge, the gas evaporates from the carb, which is virtually empty when you try to start the motor. The result is LOTS of cranking, just to fill the carb back up.

I installed an outboard motor primer bulb just before the fuel pump. Before heading to the landing (just down the street) I pump that bulb a half dozen times to fill the carb with gas--and it takes that many pumps to do it.

An alternative solution would be to install an electric fuel pump in the system with a momentary (push to run) switch. At the ramp, you simply hold that switch down for a few seconds before cranking her over. (I plan to add such a system this winter.)

Jeff

PS: You didn't mention what carb you have. I have a few tricks to make them behave as well.
 
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Try shutting off the fuel valve feed when running on muffs and letting it run for a few seconds before leaving for the marina... not enough to stall from lack of fuel. It is possible that driving around with a full bowl had fuel sloshing into the carb ans flooding the engine. Also which carb??? the TKS???
 
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Not from what I've seen. Every time I left the Edelbrocks on my old inboard alone for a week, they were practically empty of fuel.

Jeff
 
Hmmm...it's a 4 barrel, factory mercruiser carb, I want to say a quadrajet, but not positive. Whatever came with the 1994 5.7 Mercruiser 4 barrel with thunderbolt iginition. Definitely 4 barrel. Originally I would put the throttle forward a bit and it would start, but wanted it to start better, so had the carb rebuild done. I'm located in Phoenix az, so it's hot, was possibly thinking vapor lock type situation, but not really sure. Wish I had more info for you gents, i just trust that the mechanic set the choke right. Only advice I ever got was to push button on throttle to out in neutral, pump a couple times, and crank away. I would sometimes pump a few more times while cranking, I can smell gas sometimes after cranking a while
 
And it cranks, then ALMOST catches like it's going to start, then I take a break, crank some more, almoooooost catches, then fires....
 
Probably last of the quadrajets......

If the float bowl is full and the choke is set correctly, there's no need to 'pump the throttle' especially in the afternoon sun in AZ.....
 
Probably last of the quadrajets......

Ayuh,.... Or the 1st of the Merc/ Weber/ Carter AFB carbs,.... Love mine,....

Even though they're known to leak off over time into the intake,....

Exact same carb, parts interchange, with the edelbrock 1409,....
 
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