Nitrous Pop out exhaust
03-31-2016, 12:13 PM
#1
Nitrous Pop out exhaust Ok, strange question here. Trying my best to remember exactly what happened
I have a 5.3 in a Jet boat that has HCI (carbureted deal) it has a NOS cheater plate with 150hp jetting (63/55)
Ran the boat on Saturday and the boat was running very strong, actually stronger than it ever has. Burned up quite a bit of fuel, my driveability issues are finally resolved and the thing is dialed.
The way a jet boat loads the engine down is quite different than in a car. Say you are cruising along on plane at 3k rpm. You flat foot it and it will pull to your max rpm and sit there. in my case, off the bottle it pulls to 5k and sits there. On the bottle, i get to WOT then spray and it pulls to about 6-6200 and sits there.
I was on a nitrous run and towards the end of the run a rogue wake came up and i hit it. Boat came out of the water and hit the rev limiter for a breif second.
My nitrous is on a button on the steering wheel. I lifted off the nitrous as well as the throttle and stabbed the throttle again so i didnt stuff the bow.
Here's where things get foggy... I dont remember if i lifted off the throttle or the nitrous first. I dont know if it hit the rev limiter on the bottle, off the bottle. I really dont know.
What i do know is, that it popped out the exhaust and stalled. Flooded it and took me a few seconds of cranking for it to start again. According to my friends it spit about 4' flames out the exhaust when it popped.
The engine runs strong and does not seem to be damaged. I pulled all 8 plugs and they all look good. And i did do some more runs afterwards and the engine ran the same as always.
My question is, what could have happened? To cause it to pop and die? Maybe i lifted off the throttle while spraying for just a milisecond or so. Then stabbed the throttle thus adding a lot more fuel and it stalled/backfired?
it does not appear to be damaged. Id like to hear your thoughts
I have a 5.3 in a Jet boat that has HCI (carbureted deal) it has a NOS cheater plate with 150hp jetting (63/55)
Ran the boat on Saturday and the boat was running very strong, actually stronger than it ever has. Burned up quite a bit of fuel, my driveability issues are finally resolved and the thing is dialed.
The way a jet boat loads the engine down is quite different than in a car. Say you are cruising along on plane at 3k rpm. You flat foot it and it will pull to your max rpm and sit there. in my case, off the bottle it pulls to 5k and sits there. On the bottle, i get to WOT then spray and it pulls to about 6-6200 and sits there.
I was on a nitrous run and towards the end of the run a rogue wake came up and i hit it. Boat came out of the water and hit the rev limiter for a breif second.
My nitrous is on a button on the steering wheel. I lifted off the nitrous as well as the throttle and stabbed the throttle again so i didnt stuff the bow.
Here's where things get foggy... I dont remember if i lifted off the throttle or the nitrous first. I dont know if it hit the rev limiter on the bottle, off the bottle. I really dont know.
What i do know is, that it popped out the exhaust and stalled. Flooded it and took me a few seconds of cranking for it to start again. According to my friends it spit about 4' flames out the exhaust when it popped.
The engine runs strong and does not seem to be damaged. I pulled all 8 plugs and they all look good. And i did do some more runs afterwards and the engine ran the same as always.
My question is, what could have happened? To cause it to pop and die? Maybe i lifted off the throttle while spraying for just a milisecond or so. Then stabbed the throttle thus adding a lot more fuel and it stalled/backfired?
it does not appear to be damaged. Id like to hear your thoughts
03-31-2016, 12:48 PM
#2
FormerVendor
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Usually, the reason it pops out of the exhaust is because it's way too rich. Bring your fuel side jetting down and make a few hits,checking the plugs after each hit. Also, what's your timing set at?
03-31-2016, 12:55 PM
#3
It has made many passes (abotu 30 pounds worth) where im jetted at now. But if its rich, i do have some smaller fuel side jets. FWIW this thing hits hard as hell. Feels liek youre getting kicked by a donkey.
Im at 30* total on the bottle. I was backing it down to 26* but i tried 30 and there are no signs of detonation, and i gained quite a bit.
Think its to much timing? Not enough?