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AQ130C wonbt rev over 3700

N

NWBoater

Guest
"I'm hoping eventually to

"I'm hoping eventually to get this boat running the way it should. So far we have rebuilt the Solex's, replaced the head gasket (good compression),adjusted valves three times,new pointscondensor, cap and rotor. Checked for prop spin and to see if the exhaust was plugged. It seems to have plenty of power up to about 2500rpm but wont get ontoa a plane. It will only rev to 3700rpm under a load. If its in neutral the engine revs strong over 5000rpm. When we're running at 3700rpm under a load and remove the air filter (spark arrestor) you can see gas splattering up out of the carb throat, both carbs. We have not checked the fuel pump pressure or check valve gas supply line, yet. Nor have the carbs been synched. If you have any ideas or suggestions we would appreciate it. Thanks"
 
"You may want to synchronize y

"You may want to synchronize your carbs (either with a Unisync tool or by following the procedure in the operator's manual) and check your prop size (it may have too much pitch). Also, consider removing points and condenser and upgrading to Pertronix or HotSpark electronic ignition."
 
"The carbs are adjusted per th

"The carbs are adjusted per the manual but without a Unisync. The boat came with two props of the same size and it was running fine with those. The points system seems to be working fine. Starts right up, engine just purrs. One thing I noticed we changed the aux fuel filter (canister type) and picked up about 300rpm. This would lead me to believe there is something going on in the fuel delivery system. Iv'e put a lot of money and time into this engine and dont want to just keep throwing darts at it blindly. Suppose we could put a fuel pressure gauge inline. Thanks for your thoughts."
 
"No need to throw darts blindl

"No need to throw darts blindly. The fuel pump should give you 2-4 psi, if lower it is no good. You can check that by attaching a pressure gauge to the fuel pump discharge port (you are probably better off removing the gauge after you have done the test).

Have you tried to run the engine by hooking a jerrycan with fresh gas to the pump and see if that makes a difference? If it works that way, you know there is an obstruction in the suction line; maybe a stuck anti-syphon valve at the fuel tank or air finding somehow its way into the suction line.

Regarding the electronic ignition system, it is in fact a cheap upgrade that needs no maintenance and works far better than points. Many forum members have upgraded and all have reported excellent results. Just type the word Pertronix or HotSpark in the search function and see the results.
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"If your engine has good compr

"If your engine has good compression and spark the problem is probably fuel starvation. It could be due to an air leak at the fuel tank fitting (gas smell?) or a restriction in the line, possibly inside the tank. I presume that when the carbs were rebuilt that the same high speed jets were installed. BTW, have you checked a spark plug? How did it look? Fuel pump new or old as Rushmore?
Pls describe the dist timing procedure."
 
"Will check the fuel pressure.

"Will check the fuel pressure. The pump could be original 1975. Haven't tried a jerry can, will do that next time we're out. Seems like we're running to much fuel down the carbs, #2 and 3 plugs are kinda wet. Timing was set per spec but with pump gas and octane boost it was still pinging. Very slowly retarded the timing under a load until the pinging quit. The problem existed before and after the timing adjustment. How do the carbs act if there not getting enough fuel pressure. Seems almost like there getting to much fuel with the way the fuel is spitting back out the carb throat. When I rebuilt the carbs I installed what came with the kit. I will check into the electronic ignition. Thanks"
 
ARE THE PLUG WIRES ON CORRECTL

ARE THE PLUG WIRES ON CORRECTLY? OR DO YOU HAVE AN INTAKE VALVE PROBLEM? TRY A LEAK DOWN TEST ON NUMBERS TWO AND THREE AND SEE IF ANY AIR ESCAPES.
 
"Wow! Do I have egg on my face

"Wow! Do I have egg on my face went back to the basics last night. Some how I got it in my mind the crank rotated counter clockwise of course that reversed the 2 and 3 cylinder wires. Once I noticed that the BTDC marks only came up correctly if you were rotating the engine clockwise I realized I better check the rotor rotation and there it was. What an easy fix but I had made it so complicated over the past month. So it was no supprise to come in this morning and find someone had suggested plug wires, thanks Darow. You can yell at me any time if you've got the right answer, ha ha. Thanks everyone for all your help."
 
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