volvo 125a trouble

[tatoodan]

I have an 83 bayliner with a 125a and a 270 outdrive . the problem is that when the rpms get to about 3000 the motor cuts out and sputters . I have allready replaced the entire ignition and starting systems,cleaned the carb and replaced the gas .I also put a new fuel pump in.the motor runs fine at low rpm and in neutral. it only acts up in gear and has run perfect in previus years. please help I am stuck

 

[Don S]

Re: volvo 125a trouble

List of possible causes of low WOT.
I would be seriously looking at item 3

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation
• Remote control cables and linkage for proper travel to open throttle plates fully.

 

[tatoodan]

Re: volvo 125a trouble

I have allready checked the anti siphon valve, pickup tube and lines . the only things I havent checked are the compression and the exhaust shutter. I know there used to be a rubber flap on the outdrive down by the prop this has been gone for a long time. is that it or is there another one inside that I am missing ?
somone else told me to check that but I can't find any reference to that in my manual

 

[Don S]

Re: volvo 125a trouble

I have allready checked the anti siphon valve, pickup tube and lines

But did you actually put a gauge on there and check. A loose connection on a fitting or hose will allow it to suck air, and can (and will) cause the problem. With the gauge and clear hose you will be able to know for sure.

I know there used to be a rubber flap on the outdrive

That is the only one.

 

[tatoodan]

Re: volvo 125a trouble

I have not done the test ,I have checked every thing several times .I will preform the test and I will check the compression today and post the results. thank you for your help.