First time to try boat

Today i finally got to put my 4.3 v 6 new rebuild engine on the water we have had it running with the hose and all goes well starts and runs also idles down fine goes into gear and reverse all systems seem to work put it into the lake today went out through the harbor just ran fine then we opened it up a bit to 2000 rpm and it started to back fire a bit it got no better after i tried to adjust the distributor . Knock it out of gear and it climbs to 2500 rpm without a miss and sounds good back in gear and it starts to miss fire or back fire around 1700 rpm . any thoughts of where i should start looking would the prop at a to great a pitch cause that. just hunting for clues thanks mike

First of all, properly time it with a light and leave the distributor alone. Was that prop with the rig before?

Jeff

The prop was with the boat when i purchased it but they never tried it as they froze the engine now it is at home i will reset the timing to the book have been reading other peoples problems should i replace the coil and spark plug wires and cap but i don't want to start throwing parts at it because if it will not run i would rather buy a new distributor with all electronics in it from chicago company mike

Just went to check the prop its a SS 14.2 x25 mike

Sounds like it's not getting enough fuel under load. Did you do a fuel flow test? I'm guessing it is a carbureted engine, yes? Ethanol conundrum?

HI it did feel like starved of fuel went to see my friendly boat repair man this morning and we chatted about it he was of the thought the plug wires were wrong came home and checked again with a lot of make sure and found i had 3 and 5 plug wires around the wrong way i bet that was the cause of it not running correct !!! going to change the prop to the other one that came with the boat and will report back with more problems or just a smiley face mike

Hi report It works like a dream 3000 rpm 20 mph as fast as i would take it smooth as silk not a miss with the smaller original propeller

I could see that with a drive ratio of 1.98 but teV6 is only 200 hp and thats too much pitch

Hi I just went out to look its still running 14 x23 but its a large difference mike