350 hard to start

[pnhigg]

I know this isn't an uncommon question, but hopefully I can get some insight on the best place to start.
I have a '95 2130 chaparral with a 350ci mercruiser with a quadrajet on top. The boat is generally a little slow to start at the ramp, but once running idles great, comes off idle great, pulls hard all the way to wot. It really runs great, but is hard to start. I have to crank on it a while each time I try to start after it even after it has warmed up. I really don't mind the initial hard starting, but wish it would start easier after warm as we ski and tube a lot thus there are potentially lots of start cycles in a day on the water.
It seems that it is flooding itself as I generally get a pretty good puff of black smoke after it is running and I get some soot on the back on the boat. I do not pump the throttle when trying to start, but have on occasion opened the throttle wide open to start and that seems to help slightly, but I really can't tell much difference as it still has to crank a while before starting.
I have only had the boat a few months, and overall is great, just want it to start easier. The boat I traded had a 4.3 with a 2 barrel Rochester that literally a bump of the key had it running.

thanks for any help you can offer
Patrick

 

[Scott Danforth]

you have a carburetor.

with motor cold, you need to press the button in the pivot of your controls, move the throttle forward at least one full pump (this sets the choke and primes the engine), then bring back to about 1/4 to 1/3 throttle. then crank to start. once it starts, back off the RPM to about 1000, let warm up for a few minutes then go boating.

when you are opening the throttle fully, you are also pumping fuel into the engine, that is why the motor starts a bit better and the choke gets set.

if my boat sits for more than 3 weeks, I need 2 full pumps, then I turn the key, if it doesnt start, I pump it once more as the fuel in the bowls may have evaporated a bit.

the boat you had with the 4.3 may have had a TKS system if it was a 2005 or newer

 

[JASinIL2006]

My carbed 350 Mag requires pretty much the process Scott Danforth describes. Sometimes it takes even more to get started when cold, but the process he details is pretty much spot on.

 

[pnhigg]

Thanks for the input. I should have mentioned that the initial starting process is as described above. 2 full pumps then crank for a while to start. The more annoying issue is that is about as hard to start after it is warm. I know carburetors are more temperamental than efi, but I have had several that start just as quickly. The previous boat was an '85 and it started quicker than my 2010 5.3 in my truck.
Just looking for the best place to start

thanks again

 

[Scott Danforth]

If its still hard to start when its warm, time to pull the carb apart and give it a good cleaning.

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Sounds like the carb needs a rebuild,.....

Those carbs are known to leak internally,....

It starts hard cold because the bowl is empty, 'n the fuel pump has to fill it,....
They start hard warm because the leak floods the motor, advancin' the throttle to Wot usually helps,....

 

[pnhigg]

That is the most consistent answer I seem to have gotten related to the quadrajets. Ill pull it apart and rebuild and check for leaks at the welch plugs.
thanks!