Carter carb issues, electric fuel pump, hard starting

Hi Howard,

I think you’re running 427s with carter carbs, so if I’m wrong please let me know as the answer may be different.

First thing I’d do would be to toss those ignition points and install Pertronix Ignition. It’s simple, cheap, and very reliable.

Secondly, I would wire the chokes on your carters wide open, as they’re more trouble than they are helpful, because once the motor is hot and you’re out running, if they malfunction, it can lead to a very rich charge and possible flooding. I’d rather have more difficulty starting, than difficulty trying to figure out what those crappy choke assemblies are trying to do..

Electric choke kits, and electric choke carb replacements are available, but in reality these run no better when the engine is hot, than the stock carter does. Rebuilding these old carbs is a simple task. You might consider doing this before next season.
I think your starting problem is generic with the carter carb. In other words, I believe just about everyone with an original Commander has the same issue. The carbs don’t atomize well at cranking speed. The carters will either slightly drain down or evaporate fuel from the bowl, and this makes starting a bit of a challenge. You’ll notice that if you run in the morning, and then try to start in the afternoon, the motors will probably fire right up because the carbs are still primed up and ready to run. There is a very simple solution, however, and it is NOT electric fuel pumps. More about that later.

The solution is to pump the throttles and then catch the motor before it stumbles. It is very simple but it takes a bit of practice to know just how many pump strokes it will take, depending on the carb and the time it has been sitting up.

Knowing the fuel may be low in the carb bowl if the boat has been sitting a while, if I have not run the motors for a while, I always pump the throttles 10 to 15 times. If it’w been two weeks, perhaps more. What this does, is put enough gas vapor into the intake manifold to cause the cylinders to light off, but it also further drains down the bowl. This vapor is getting to the motor from raw gas dumped into the intake manifold instead of the carb being primed by continuous cranking up to the point where it will atomize fuel enough to start. This assumes your chokes are junk like 99.9% of all marine chokes are on Carters. If you get enough raw gas pumped into the intake manifold, the motors will catch just fine, but the fuel bowl may take just a few seconds to fill up with that fuel pump pumping away.

What I do is crack the throttles open far enough to provide a 1500 RPM engine speed. This takes a little practice. When the motors start, then will very quickly build up fuel pressure, but they may want to stumble a bit, so be prepared to jab another squirt of gas to keep engine speed up high enough for that initial fire up. Crank crank, varooooooommmmmm, burble burble, start to cough just a bit, give it a bit more gas before it stalls, and varoooooommmmmm and running fine at 1500 RPM fast warm up idle speed for a short while, and then back off so as to not scare all the rest of the people out of the marina. It may take a few times to know just how much fuel to pump, depending on how long the motor has been sitting.

I’ve heard a lot of comments about electric fuel pumps, but I don’t like them on a boat. There are literally MILLIONS of cars still out there running with traditional fuel pumps, and just doing fine, pumping a lot more fuel than our 300 hp detuned 427 motors need at a max of (only) 4000 RPM. This is 2000 RPM less than the factory warranted speed of some of the higher performance motors, by the way, and I’m sure the carbs and pumps were different too, but the point is, 4000 RPM really doesn’t put that much of a demand on a fuel pump.

I don’t like electric pumps because they’re one more electrical component tied to switches, connections, batteries, that can corrode in a marine environment and fail. The mechanical pump is a slave situation, and it is almost “dead reliable”. Why go to something that certainly has a higher probability of failure? Answer: 427 fuel pumps are difficult to get to, and this is the reason some go to the electric pumps. If you use an electric pump, in my humble opinion you MUST use an oil pressure switch to shut off the pump if pressure drops with the motors running, to avoid pumping raw gas into the boat in the event of some sort of engine failure or emergency situation, and this is just one more reliability issue that can fail and be very tough to diagnose.

You can install a fuel pressure gauge to tell exactly how your pumps are working, but do NOT install the direct pressure type on a boat, because that is one more very serious safety issue you will be flirting with and there is no need to do so. Also, I would think a sharp USCG or marine surveyor inspector would see this and write you up. If you use a fuel pressure gauge, in my opinion, you must use one with an electric sending unit.

I do not view electric pumps to be the panacea some do. I view them to be sort of an easy way out approach to not replacing the standard pump. I would rather adapt to the starting procedure noted, than have the danger and potential unreliability factor associated with so many additional electric connections, etc.

If you want instant starting you can go with a new marine carb (“marine”) with electric chokes, or you can simply adapt to the routine I’ve noted here. Personally, on a boat I like the “keep it simple” format, and with fewer things to go wrong, fewer things “will” go wrong. I understand there have been elec fuel pumps in operation (often as the “cheaper” and “easier” solution) for years, but I personally don’t like the corrosion issue in a marine environment, and I also don’t like the potential safety issue.

Hope this helps a bit.

Regards,
Paul