96 dd 350 only getting to 2500 rpm

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redneck0194
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96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

14x7.5 combee dd 350 2 blades h series
Motor will only spin to 2400 rpm advanced the distributor got to 2500 rpm
Moved blades to pitch 2 setting stayed at 2500 rpm
What can I do to get it to spin 3000
Boat is on dry ground
This is my first boat any help would be nice
Thanks ahead of time

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john1edwards
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Re: 96 dd 350 only getting to 2500 rpm

Post by john1edwards »

go to 1 or 1and half mark. I think I ran mine at less than 2 on my 1972 350 chevy. that prop like 3000
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redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

Ok I'll try that
Just wondering shouldn't it change the Rpms through each pith setting

SWAMPHUNTER45
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Re: 96 dd 350 only getting to 2500 rpm

Post by SWAMPHUNTER45 »

If the prop is correct for the engine if you start at 1 on the marks you should be getting to your targeted RPM and more.

Once you start to exceed the max PRM you add pitch to reduce the RPMs to your desired sweet spot.

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Re: 96 dd 350 only getting to 2500 rpm

Post by Olf Art »

Also, advancing the ignition can cause problems of it's own. Block you vacuum advance and set your timing so that it never creeps
past 32 deg. total advance. All things being equal, you'll solve the rpm problem by where you set your pitch.
At 3,000 rpm that engine (if it's in good tune) is only gonna be making a little over 200hp. You can't load it down too much with
the prop.
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redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

Ok I'll do that is there any thing I can do to the motor to get more hp without breaking back into the motor
it's a fresh rebuild

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keebo
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Re: 96 dd 350 only getting to 2500 rpm

Post by keebo »

Is it stock?

And as for more power without breaking back into the engine you can set the prop for correct rpm, get tuned exhaust, get carb tuned, put on roller rockers, better hei system, add a nitrous plate with a 50 shot and get a lighter hull, that 14' combee is a heavy boat for a DD 350
JMO

And post your location, may be someone close who can help ya.
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redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

I'm in morriston fl
Thanks for the input got home today to do some adjusting
Cranked the boat an motor warmed it oil pressure dropped
To around 10 psi
Wen first started was around 40 psi At the port behind the distributor
50 psi at the port above the oil filter
Then both dropped to around 10 psi at idle
At WOT was around 25 to 35 between the 2 gauges
It has new cam bearings not ruling them out but
Anybody else had this problem or some help
If you need more I do let me know I don't want to loose the motor

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Re: 96 dd 350 only getting to 2500 rpm

Post by SWAMPHUNTER45 »

So this was a recent rebuild?

redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

Yes motor doesn't even have 5 hrs on it yet never seen water yet

SWAMPHUNTER45
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Re: 96 dd 350 only getting to 2500 rpm

Post by SWAMPHUNTER45 »

Is it a flat tappet camshaft or roller?

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Re: 96 dd 350 only getting to 2500 rpm

Post by loudmouse »

U need to check oil for metal and also oil filter. Something is wrong if new parts were used
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keebo
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Re: 96 dd 350 only getting to 2500 rpm

Post by keebo »

Some chevy small blocks just do that, idle @ 10-15 warm, it could be several things, bearing clearances, by-pass plunger in pump stuck open, maybe some rvt in it? Cam bearings aligned correctly for oil passage, spun cam bearing. Or might just idle that way warm with nothing wrong. Check your pump first if your concerned
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redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

Oil looks clean I'm gonna cut the filter open tomorrow

SWAMPHUNTER45
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Re: 96 dd 350 only getting to 2500 rpm

Post by SWAMPHUNTER45 »

What oil did you put in it ?

Did you use Lucas or any other additives?
Last edited by SWAMPHUNTER45 on Wed Jan 21, 2015 9:00 pm, edited 1 time in total.

redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

How do I check the oil pump

redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

I have 15-40 syn.

SWAMPHUNTER45
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Re: 96 dd 350 only getting to 2500 rpm

Post by SWAMPHUNTER45 »

OK this is a real worry from my experience. If you just started up a new build with say Mobil1 or RoyalPurple and didn't use a Zinc additive like CompCam159 you may be making metal. It is a possibility, immediately check oil filter before you do anything else.

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dodobird
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Re: 96 dd 350 only getting to 2500 rpm

Post by dodobird »

only takes 5psi to float a crank at idle imo :florida: specs are 30psi at 2000 rpms on stock 350
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redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

It's a roller cam
I'll cut the filter open tomorrow an let y'all know what I find
What's has me worried is there is no noises no taps pings
It just runs smooth

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keebo
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Re: 96 dd 350 only getting to 2500 rpm

Post by keebo »

Not being smart but if your asking how either let someone do it or you tube it, easier then explaining on here.

Also, chevy reccomends 10 psi per 1000 rpm, is motor stock?, hv oil pump? Lots of variables going on.
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dodobird
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Re: 96 dd 350 only getting to 2500 rpm

Post by dodobird »

SWAMPHUNTER45 wrote:OK this is a real worry from my experience. If you just started up a new build with say Mobil1 or RoyalPurple and didn't use a Zinc additive like CompCam159 you may be making metal. It is a possibility, immediately check oil filter before you do anything else.


x2 if it aint a roller cam u need additive :florida:
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SWAMPHUNTER45
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Re: 96 dd 350 only getting to 2500 rpm

Post by SWAMPHUNTER45 »

Less to worry about!

He PM and said it was a roller cam
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redneck0194
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Re: 96 dd 350 only getting to 2500 rpm

Post by redneck0194 »

It's a melling m55hv high volume high pressure oil pump

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dodobird
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Re: 96 dd 350 only getting to 2500 rpm

Post by dodobird »

stock pan? hope u aint suckin ur pan dry :florida:
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