Power loss in Port engine (re: Port engine running rough)

I changed everything in the fuel side per my last topic. (re: Port engine running rough)
New fuel, new filters. I took the boat out and the Port engine still runs rough. It started up good and in neutral it sounded good. When I stick the Port engine into gear it runs rough and I smell gas again in the exhaust but not as bad as my first listing. I ramp the engines up to speed and for some reason the Port engine would not go over 2500 rpm’s. It just felt like something was holding it back. Gas smell was still around and I also noticed when I was doing 2500 with both engines and doing about 16-17 knots the Port engine had a lot of steam coming out the exhaust, more then the Starboard side.
I checked the engine oil to see if there was water and that was ok. I checked the tranny and that was fine.
I had a couple of possibilities it might be but could use your help:
1) Could a bad battery help in losing power? I have 1 battery for the Port engine only.
2) could it be the carb? Might need it rebuild kit and cleaning

I will say that the boat ran well and the port engine did not give me the same trouble as the first topic (port engine running rough) it stayed at 650-700 rpm’s at Idle unlike last time. I did notice more fuel was being used on the port side. I was doing 2500 rpms on both engines and the fuel meter on the port side showed 16 gallons per hour where the starboard was at 10 per hour. I don’t know if that tells you anything or not.

Thanks for your help team.

I skimmed your last post and didn't see anything about a detailed carb inspection, only changing filters.

Have you checked the sight tube to see if the fuel pump diphragm is busted?

did you check the ignition advance to see that it allows full advance?

The gas consumption numbers lead me to rank them most likely first.

If they are both ok, check the carb gasket (air horn) and see if it is wet. That's a good indicator of flooding. If that's it, make sure you get a good needle, a good inlet seat (of the proper size) and a new float as well as a new air horn gasket. and get two as the ethanol is probably chewing on the other side right now.

makomark:
No on the Carb anything besides cleaing it with carb spray.
I did not check the ign advance, I would need someone to do that.

I got to speak with some good mechanics this weekend about the lost of power
On the port engine and the smell of gas. I’d say 98% feel it’s the carb. Most claim that if the float and some of the pins are not working correctly the engine will run but real rough and get real bad mileage. They all said find a good mechanic that’s knows how to do a rebuild on carbs.

I looked on line to see if I could just buy a new carb, part # 17059293 quadrajet 4bb manual choke. I could only find rebuild kits and the float.

Is there any good places to look?

Our site host, Andrew, can probably get you an overhauled one.

Don't be surprised if a rebuilt one comes in with a different casting number.

makomark said:

did you check the ignition advance to see that it allows full advance?

Click to expand...

I'll second Mark's suggestion on this.
If the ignition distributor (or ECM/ECU) is not providing the correct advance curve, the engine will not produce the power that you need.
No progressive spark lead..... and no power! Simple as that!
See your OEM specs for this curve and "full-in" advance and at which RPM this is to occur!

Also, the beauty of twins allows for a simple swap of these carburetors.
The cost is a bit of your time, and two new base gaskets.
Pretty inexpensive way to eliminate or determine if this is the cause.