1999 Sea Doo Challenger 1800 Engine problem

[SIP]

Hi All,
Just purchased a 1999 Sea Doo Challenger and the person I bought it from said he had just rebuilt both engines and pumps and they have only 20 hrs on them. He hasn't used it for about 2 years and when I went to see it it fired right up nicely. When I got it home and went for a test run it ran horribly and would not hold any rpm over 3000. I thought it was bad gas so I pumped the tank and changed the fuel filters and pulled the carbs to have a look. Wow..he did not winterize the engines or they were just sitting too long without movement but the carbs were rusted and very dirty. I cleaned all 4 carbs completely, I did not use a rebuild kit but they cleaned up nicely and the rubber was still in good shape. Took it out today and the left engine ran great and the right engine started out running great but after about 5 minutes of high rpm running it would go from 6500 rpm to about 3000 rpm....up and down and up and down....I tied chocking it a bit to see if it would catch but it just died. Wondering what I should be considering with the fluctuation of rpm? Perhaps I need to clean the fuel pumps and rave valves as well? Thanks for your help! SIP

 

[racerxxx]

Welcome to the forum. First you could do is swap fuel pumps, see if the problem follows. I would run it long enough to just see the problem. Change out the spark plugs. And do a compression test, getting spark plug wires, throttle wide open and crank over the engine. 150psi per hole is what your looking for. Be careful if you open the fuel pumps, you can not get replacement parts and usually the main gasket stretches so bad it makes it difficult to reseal.

 

[howie099]

Pumps I would just replace with universal pumps or look for the oem mikunis. U can clean the raves also. You can switch the carbs and fuel pump around also to see if it is fuel related.