SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: czomega77 on September 13, 2015, 02:02:17 PM
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Hey guys looking for some info on my motor's rpm's its a stock 454 in a 2002 cobra open bow with a legend pump a cut impeller and It tops out at 4200 rpm is that correct? Thanks
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IMHO your about 300 rpm short.
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That what I was thinking from reading other posts but wanted to ask. What should I start looking at first to fix this problem?
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That what I was thinking from reading other posts but wanted to ask. What should I start looking at first to fix this problem?
Start with the obvious.
Tune; timing, fuel pressure, spark plug gap, jetting, throttle linkage etc.
Pump Condition; impeller blade condition, debris etc.
Check tach; accuracy?
It gets more expensive from there.
GT
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We are in the exact same situation. My 454 tops out at 4200 as well. I will keep you updated with what works for me. Next trip out I am changing the ignition module, flame arrestor and hopefully carb. I'll let you know if I am able to spin more rpm.
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I'm going to make some adjustments and check everything next trip and see what happens I'll update as well
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Mine tops out at 4400, I'm running a 780 holley vacuum secondarys an accell hei and an edelbrock manifold stock a cut aluminum impeller
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Mine tops out at 4900, running demon 850 carb, mag ignition....
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Mine tops out at 4400, I'm running a 780 holley vacuum secondarys an accell hei and an edelbrock manifold stock a cut aluminum impeller
This is a tad shy for a 330 hp 454, could be tach inaccuracy, or needing a little more timing, if everything else checks out OK.
My ~ 330 hp 350 was at 45-4600 rpm with an A. (It did have O.T. headers)
Hey guys looking for some info on my motor's rpm's its a stock 454 in a 2002 cobra open bow with a legend pump a cut impeller and It tops out at 4200 rpm is that correct? Thanks
Like GT said, about 300 or so rpm short.
I tend to stay conservative on timing but it seems a BBC likes about 12-14* initial, or 32-34* total
Mine tops out at 4900, running demon 850 carb, mag ignition....
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Mine too, 750 holley VS, GM HEI, logs and snails, 4900-5k, AA impeller though
Dan'l
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Your right I'm down to a 105 psi in 6 cylinders and 85 in #1 & 6 going to be putting a new engine in and rebuild the pump this winter, still hits 53 on GPS.
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Your right I'm down to a 105 psi in 6 cylinders and 85 in #1 & 6 going to be putting a new engine in and rebuild the pump this winter, still hits 53 on GPS.
Throw a squirt or two of oil into #'s 1 & 6, and run compression check again
no change...valves
big change...rings
Also check the cam lobes on #'s 1&6 (flat?)
standard bore motor? how many hours on it? Maybe it needs a refresh- rings, bearings, hand lap the valves, new cam, oil pump and gaskets...weekend project :thumbup:
Dan'l
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Throw a squirt or two of oil into #'s 1 & 6, and run compression check again
no change...valves
big change...rings
Also check the cam lobes on #'s 1&6 (flat?)
standard bore motor? how many hours on it? Maybe it needs a refresh- rings, bearings, hand lap the valves, new cam, oil pump and gaskets...weekend project :thumbup:
Dan'l
I did it's the rings ,when I bought it, it had 325 hours on it two years ago since then I've put another 300 hours on it, LOL ,I just ran it from Laughlin to pirates cove on Saturday, the wife and I run the heck out of it, for us it's nothing to leave the islander go to the casino for breakfast head over to pirates for lunch and Havasu springs for dinner in a day!
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Yeah its an 89 standard bore peanut plug head, I want to throw a 496 in it
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I did it's the rings ,when I bought it, it had 325 hours on it two years ago since then I've put another 300 hours on it, LOL ,I just ran it from Laughlin to pirates cove on Saturday, the wife and I run the heck out of it, for us it's nothing to leave the islander go to the casino for breakfast head over to pirates for lunch and Havasu springs for dinner in a day!
Throw a can of Restore in it. That shit works.
GT
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Throw a can of Restore in it. That shit works.
GT
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That's funny you said that I meant to do that this weekend and ended up adding a quart of oil, I use to run it in my old Plymouth station wagon tow car.
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Was just gonna post the same question about my Indmar 454. Hittin about 4400 with an A cut in a 19ft Commander SS. Doesn't seem to want to top 43 mph... 👎👎👎👎
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Was just gonna post the same question about my Indmar 454. Hittin about 4400 with an A cut in a 19ft Commander SS. Doesn't seem to want to top 43 mph... 👎👎👎👎
Better check your tach or impeller. At 49 I'm spinning 4200 and I got 2' on you
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Better check your tach or impeller. At 49 I'm spinning 4200 and I got 2' on you
Yeah gonna try a couple things...