HELP 200 johnson venom

[crob37]

Here's the story:

bought a 97 cajun with 200 johnson outboard venom. Boat has been sitting for several years. Drained old gas, changed out plugs and took the boat out. Boat would not plane out, would not get above 2500 rpms. It cranks every time but does not have power. Took to mechanic, they decarbed carburators, changed plugs, checked compression. They took boat out for a test run and said it ran fine.

Got boat back and took out and for the first 15 minutes ran good and then it started to lose power, would not plane out. So I put in neutral and reved up the motor seems like it reves up good and put in gear and still just will not plane out, It also dies after I let off the throttle, but it will start right back up. Gas cap broke off, so I have the port plugged up to keep fuel from spilling out of the boat.

What could be the problem, what do I need to check.

Thanks for any help....

 

[Chris1956]

Re: HELP 200 johnson venom

water in the gas? Dirt in the fuel? If so, you may have dirt/water in the carbs. Drain them and see if water comes out. Clean the fuel filter or strainer.

 

[d.boat]

Re: HELP 200 johnson venom

Here's the story:

bought a 97 cajun with 200 johnson outboard venom. Boat has been sitting for several years. Drained old gas, changed out plugs and took the boat out. Boat would not plane out, would not get above 2500 rpms. It cranks every time but does not have power. Took to mechanic, they decarbed carburators, changed plugs, checked compression. They took boat out for a test run and said it ran fine.

Got boat back and took out and for the first 15 minutes ran good and then it started to lose power, would not plane out. So I put in neutral and reved up the motor seems like it reves up good and put in gear and still just will not plane out, It also dies after I let off the throttle, but it will start right back up. Gas cap broke off, so I have the port plugged up to keep fuel from spilling out of the boat.

What could be the problem, what do I need to check.

Thanks for any help....

do you have a water separating filter? This is a critical item, in my opinion, and if you don't have one, you can get repetative water and contamination problems. You might have to start over again.

When you say "decarbed carbs" what do you mean? "Decarb" refers to a treatment that removes carbon buildup from the pistons and internals of the engine (see FAQ). Cleaning carbs is a different thing and genearlly involves taking them completely apart, soaking and replacing certain parts, a fairly involved process (also see FAQ). Spray-through carburetor treatments are not generally considered effective.

Anyway, you (or the mechanic) should have gone through the entire "waking a sleeping outboard" process described in the FAQ's. Regardless, I think you might have to start at the beginnig - compression, spark, fuel system.