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lawnmower repair man
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128 Posts
Discussion Starter #1
its A heavier hull 75 18' challenger fresh berk pump, Diverter stuffer with a bronze B. All new boat really. All new guages. Mtr is a mild 454. flat tops its maybe 10 1/2.1 cams like 580ish lift, tunnelram with dual edlebrock 500's. motor is FRESH. msd dist with the msd6 box. Pulls real good out of the hole mid seems to stop at 3300 just as its starting to go.... At first I thought the tach was wrong still kind of do Its no race motor but seems a bit weak to me. lean timing hits the brakes that much?
 

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What cyl heads ? A typical 119cc comb chamber with typical 'flat tops' in a 454 = 8:1 compression or so.
 

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lawnmower repair man
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128 Posts
Discussion Starter #3
What cyl heads ? A typical 119cc comb chamber with typical 'flat tops' in a 454 = 8:1 compression or so.
you are prob right. I believe the motor is a 1978. He had some head work done when the motor was rebuilt. maybe just lack of torque. but 3300 rpm?
 

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What's your total timing at 3000 rpm?
Good question. Let's add to this....

Is the throttle cable adjusted to allow the carbs to open fully?

Are the secondaries even opening?

Are you sure the tach is accurate?

What speed did you see at 3300rpm and how does that compare to speed before this work was done?
 

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Good question. Let's add to this....

Is the throttle cable adjusted to allow the carbs to open fully?

Are the secondaries even opening?

Are you sure the tach is accurate?

What speed did you see at 3300rpm and how does that compare to speed before this work was done?

Good call ,What he said !! :D Tom
 

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E-7 Sheepdog (ret)
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You have a problem of SOME KIND.
3300HP on a B is only arround 90HP requirement.
 

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Boat Nut
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Most boats won't even plane off at 3300 rpm's, especially if your running a "B" impeller.
# 1 check that tach

# 2 check the fuel pressure and float levels

#3 total timing and read the plugs.

Answer these questions, then you will get you will be headed in the right direction.
 

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B.A.M aka "Black Azz Mike
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2,925 Posts
Barrett, what are you up to now?
 

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B.A.M aka "Black Azz Mike
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Drop one of them Grose motors in there and run it:D It will see more than 3300:D
 

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lawnmower repair man
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128 Posts
Discussion Starter #11
Drop one of them Grose motors in there and run it:D It will see more than 3300:D
its my old old mtr. its fresh tho. I do not think the tach is right. im thinking timing 36-38 at 3000rpm let er rip. I just went for a ride I didnt have time to help him. I think it sounded like 4300rpm. he put 2 500cfm edle's on a ram. Not sure what the jetting is, think he said feul press at 5. we were getting 3k rpm and adv timing a tiny turn, then he got 3300rpm. He used to have a olds 455 in it, he ran 62 or so with it. To me it seemed at the suposed 3300rpm we were goin 60. does the msd 6a box have cyl type options like the 6al? I tell ya tho it LAUNCHES straight out and gets with it, just seems to stop. :))eek:)):))eek:))
 

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its my old old mtr. its fresh tho. I do not think the tach is right. im thinking timing 36-38 at 3000rpm let er rip. I just went for a ride I didnt have time to help him. I think it sounded like 4300rpm. he put 2 500cfm edle's on a ram. Not sure what the jetting is, think he said feul press at 5. we were getting 3k rpm and adv timing a tiny turn, then he got 3300rpm. He used to have a olds 455 in it, he ran 62 or so with it. To me it seemed at the suposed 3300rpm we were goin 60. does the msd 6a box have cyl type options like the 6al? I tell ya tho it LAUNCHES straight out and gets with it, just seems to stop. :))eek:)):))eek:))
All above are good places to look but cam timing could be a problem. Launches like a bullet and lays down at 3000 RPM???? What timing gear and chain set did you use and who set it up????????? I have seen a Cloyes with all the different Boxes,Triangles and zeroes mess with a few minds. B cut bronze and a big block "STOCK" should go atleast 4800 rpm
 

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NW Spectraholic
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588 Posts
So how many Rs would the Olds pull?

I'll say it... Should'a kept it! ;) :D

What number heads? If they are open chamber I hope the pistons aren't really flat tops...
 

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lawnmower repair man
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128 Posts
Discussion Starter #14
All above are good places to look but cam timing could be a problem. Launches like a bullet and lays down at 3000 RPM???? What timing gear and chain set did you use and who set it up????????? I have seen a Cloyes with all the different Boxes,Triangles and zeroes mess with a few minds. B cut bronze and a big block "STOCK" should go atleast 4800 rpm
It is a cloyes, the motor is a bit more then stock. It worked well in my old 71 sanger would get 61-6200rpm mite have had a hun or so more I didnt try I figured going from vdrive to a jet he'd lose 600-800 rpm.? it starts good. Idles ok needs some playing with for sure. just want to help get the most out of it. He did a great job redoing the whole boat
 

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lawnmower repair man
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128 Posts
Discussion Starter #15
So how many Rs would the Olds pull?

I'll say it... Should'a kept it! ;) :D

What number heads? If they are open chamber I hope the pistons aren't really flat tops...
haha I think he got 5200 or so out of the olds. The 454, I will dig up what heads, pistons etc. A machine shop redid the motor. the olds was fun times he rebuilt it the last time, it was strong, took it to the lake thursday for testing, everything was great. He went camping fri drove the boat sat, first trip out sun blew it up the third and final time.:)devil

So he sold the whole dead mtr, mounts etc. for 250$ gutted rotten floor, redid the inside lightened it by who knows 2-300#'s
 

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It is a cloyes, the motor is a bit more then stock. It worked well in my old 71 sanger would get 61-6200rpm mite have had a hun or so more I didnt try I figured going from vdrive to a jet he'd lose 600-800 rpm.? it starts good. Idles ok needs some playing with for sure. just want to help get the most out of it. He did a great job redoing the whole boat
Hey notathing, If it's laying down that bad at 3000-3500 rpm gotta be running out of food. Check the feul pressure and the carbs,AND Jets, if they are 500 cfm and the jetting is below #66 or #68. I would check the plugs for a color reading. Also if the carbs are vac secondaries check the vacuum can spring color. The lighter the color the less vacuum to open
 

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Hey notathing, If it's laying down that bad at 3000-3500 rpm gotta be running out of food. Check the feul pressure and the carbs,AND Jets, if they are 500 cfm and the jetting is below #66 or #68. I would check the plugs for a color reading. Also if the carbs are vac secondaries check the vacuum can spring color. The lighter the color the less vacuum to open
OOPPSS sorry holley on the brain but check the plugs for a reading.
 

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check the tach first and eliminate that. On the back of the tach there is a switch where you can can change the pulses. Make sure its set to 8 cylinder.
I'd start with the basic stuff first before digging too deep.
 
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