350 Crusaders Bogging / Stalling / Popping at high RPMs

frenz143

Recruit
Joined
May 19, 2009
Messages
5
This last winter I had both of my 350 crusaders rebuilt along with Holley carbs 12R-10658B. When I had the boat back in the water, The engines would run fine the first time I would get up on plane. Then I would bring them down and up again and one engine would start bogging down around 3,800 rpm. Then the other engine would do it on a separate occasion. They have never done it both as the same time. They have two separate tanks but I have been switching the port tank to the starboard engine and vice versa. Now it doesn't matter which tank is on what engine, it happens to both. I have at the carbs rebuilt multiple times this summer and the first time the mechanic said there was some crap in the ports. Second time there was some and third time there wasn't any. After he would clean them and reinstall, they would run fine for a minute and then it would happen again. There is no water in the fuel, i have changed the fuel water separators three times. And doing a visual check in the tanks, there is no sign of debris. Any ideas?
 

frenz143

Recruit
Joined
May 19, 2009
Messages
5
Crusader Engine Idles High When Coming off Plane

I have twin 350's in a Carver 300 Sedan that were just rebuilt. I start the engines and they both idle at 750 rpms. I will take the boat up on plane for about 10 minutes and bring it back down to idle. Except i have the throttles all the way down and it will idle at 1000-1300 rpms's. If i hit the throttle up and down fast, it will slowly bring it back to idle after a couple times doing this. Any thoughts on why this happens?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
47,296
sounds like you have fuel issues, debris ending up in the carbs. what you are describing is a lean sneeze.

start by inspecting the tanks, clean as needed. empty the fuel water filter contents into a clear jar and inspect (do not reuse the filter). pull the carbs apart and clean the passages.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,296
you have two posts on the one issue. you have a fuel issue.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
This is" other outboards" I think you will get better results in the I/O section.
 
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