Can someone help

[dado78]

Hey guys got problem after problem after problem.
I got my carb rebuild, new starter, alternator new water pump & steering pump. New oil engine and lower unit, All work good yesterday boat was going almost 50 until. Today went on boat first 10 min boat runs fine fired up right away and than all suddenly start making sound like tractor without muffler.
I will try to upload a sound of it if someone can figure out whats wrong. Change spark plugs to. If i throttle a bit nothing happen always same speed maximum 10 mph. Manage to get back on trailer but sound is bad.

 

[alldodge]

Howdy
I would do a compression test because that sounds like a valve is stuck or piston has a hole

Are you seeing any blow by?

 

[dado78]

No blow by just suddenly change the sound and will not allowed throttle to speed up. Will check today and post reply. Thanks

 

[alldodge]

Also what motor is it other then a 3.0?

Is it a GL-something?

 

[Scott Danforth]

do a compression test

 

[dado78]

No blow by just suddenly change the sound and will not allowed throttle to speed up. Will check today and post reply. Thanks

 

[dado78]

3.0 GL GM Engine. Runs perfectly in neutral but as soon throttle is move to drive sound changes and max speed 5-7 mph .

 

[dado78]

Problem solved 3 spark plug wires where shot. Even with plug puller i will get shocked and replace them and now all good. Thanks