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74 L 330 trs twins cutting in and out on top end

wayned800

New member
"Hello,
I have a 1985 baja 32


"Hello,
I have a 1985 baja 320 with two 7.4 trs 330's. started out this summer by changing water filters, plugs, wires, cap and rotor. checked fuel screen and was clean. the boat starts, idles and runs perfect on both motors until you get to between 35-3700 rpms. after that both motors act simular, they act like they are starving for fuel when the four barrels start to open. first half of summer they would run 4600 and hold no problem. I did have the carbs apart and cleaned. Did not change the float level. I have not messed with the fuel pumps. It just seems strange that all of the sudden both motors are doing the same thing. It started with one motor cutting out a small amount and after a few more times out in the lake they now are both doing it. ANY IDEA's?? The motors both have only 200 orignal hours and seem very solid. no smoke or leaks. As long as I cruise under 3500 rpms they sound perfect. I keep thinking they are starving but it seems like I am burning a fair amount of fuel. Thanks in advance for any help! Wayne"
 
Fuel is common to both. Are y

Fuel is common to both. Are you using gasohol? Do you use a fuel preservative for that fuel? I would change the fuel/water filter separators. Before installing them fill each w/SeaFoam and run the engines at idle for 3-4 mins. Let them sit o'night and run them in the morning. You can repeat the process w/o changing filters. Just empty the fuel out and fill w/SeaFoam and run the engines 3-4 mins.

SeaFoam will remove any water in the bowls and clean the inside of the carb including idle circuits. If you don't use a fuel treatment SeaFoam will work better than Stabil now made for gasohol. Cost is the difference. A 16 oz. can of SeaFoam is $9 and one ounce treats 2.5 gals.
 
"strainers in the pickup tubes

"strainers in the pickup tubes or antisyphon valves, either being clogged, will do just what you described."
 
"I really thank you for the he

"I really thank you for the help. I did not mention that i pulled the gas line pick up and it doesn't have any strainers in the tank. It wasn't cool because when I pulled the first tube it stripped because it was aluminum on aliminum and it stripped instanstly. I don't think there is a antistrainer in the system. If so, where would it be? The fuel pick up was just a tube from what i see. You could blow thru it from both ends freeely. This system has two separate pickups for each motor.
As for the Sea foam idea, I have already done that. I have thought of the bad gas idea and drained the tank put fresh gas in it along with some sea foam and it did not help. That is why I am so confused with my problem. Thanks again
wayne"
 
"The antisyphon valve is usual

"The antisyphon valve is usually at the to of the pickup. You're right, air going both ways = no valve.

All the fuel line ok....25 years old, may need to be refreshed.

How about the tank vent-open??? Quick check is to open the fill cap.

What did you find in the carbs? Did you remove them or just take off the air horn cover?"
 
I replaced the fuel line. I pu

I replaced the fuel line. I pulled the carbs and rebuilt them. I did not reset the floats. After I rebuilt them it ran fine for a few trips before they started acting up. Almost like it runs fine til the four barrels kick in.
 
"When you rebuilt the carbs, d

"When you rebuilt the carbs, did you change the air valve springs and check the hanger cam for wear?"
 
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