[alliedasset]

I have a 91 diablo with a 4.3 and mercury outdrive. It was running perfect n then we went on a nice slow 10 mile cruise at idle and then when i went to jump on itn got it to 3000 rpm it started bogging n slowly died out. n then it starts right back up. n does the same. I put fuel treatment n it n it still does it. any suggestions plz let me know what i might have to do ty

[DougR]

Does it backfire or any other issues?????

[alliedasset]

nope it runns great at idle n low speeds but when i throttel down to get some speed it gets to about 3,ooo rpm n above it starts to bog n just slows n dies outn then it fires right up n runns great. i even had it n neuatral n revved it up n it had to probs but when i start goin that when it dies

[DougR]

Ok, will it rev past 3k, if you go really slow with the throttle? If so, possible accelerator pump in the carb??? Or weak ignition issue / coil?

Accelerator pump can be checked by looking into the carb and opening the throttle (air filter off). You should see a nice squirt of gas.

Doug

[alliedasset]

How do I do it with it out of the water. Before r long slow cruise the thing ran awesome for the13 hrs I put on it. Should I also change the plugs because the rip off marina we were by said it could be the plugs also.

[alliedasset]

Slowly or fast throttle it still dies out

[DougR]

Could possibly be plugs? Due to the load on the engine that could cause it to fail but it probably backfire a little...

You could purchase "mufflers" they slip on your outdrive and allow you to run the engine using a garden hose to keep it cool...

Also, the boat shouldn;t have to be running to check to see if the carb is squirting gas..

-Doug.....

[alliedasset]

np ty the mufflers are those the things that u use to winteize it.looks like the thing a doctor wears to check ur heart n chest. ill do the plugs and take the airfilter off and see if the gas is squirting down. ty n any other pointers would help ty.

[DougR]

Yep, attach the hose. Slide it over your intake holes ( make sure to lower the drive) turn on the water and running boat in the driveway.....
How's your fuel / water filter???
Boats r hard on ignition components so have you replaced cap, rotor, wires plugs recently??

[alliedasset]

No I haven't done any of that. How do I find the parts r they the same as a 4.3 car engine. I'l do all that stuff before I consider any carb problems. It's a 91 4.3