SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: jfs.welding.fab on July 17, 2016, 12:00:33 PM
-
So I rebuilt my 455 olds and got it back in the boat, but around 4k rpm it sputters. It has a brand new edelbrock 750, all new valves, valve guides, and springs, offy tunnel ram, newer holley fuel pump, new coil, mallory single point distributor, brand new autolite platinum spark plugs. Any help would be appreciated
-
Little info
Fuel pressure?
Float level ?
Timing ?
How does it run when u take off?
Sent from my iPhone using SoCal Jet Boats
-
I'm not sure about fuel pressure, but I know it's getting enough fuel because I took the fuel line off and pumped gas onto a bottle to see how much was coming out. Timing is set right around 11* I believe. And as far a driving the boat, I have no idea, bought the boat months ago as a project and haven't taken it out yet.
-
Hopefully your pump is disconnected
While your running it on trailer
Sent from my iPhone using SoCal Jet Boats
-
Ditch the mallory single point and go hei or electronic,had the same problem years ago with a dual point mallory,it was on a bbc 461, I know it's not the same motor but symptoms are similiar
-
Which carburetor?
Your fuel test is worthless (sorry).
What fuel pump?
When you say sputters, how? Carburetor, exhaust?
Just misses?
What exhaust?
How are you cooling it?
Compression test?
Timing test is worthless too... What is the timing at over 2,500rpm?
Vacuum advance?
Why points?
How much voltage on the coil with the engine running? What coil? ....
Sorry. Had to.
GT
-
Which carburetor?
Your fuel test is worthless (sorry).
What fuel pump?
When you say sputters, how? Carburetor, exhaust?
Just misses?
What exhaust?
How are you cooling it?
Compression test?
Timing test is worthless too... What is the timing at over 2,500rpm?
Vacuum advance?
Why points?
How much voltage on the coil with the engine running? What coil? ....
Sorry. Had to.
GT
GT will get u on the right track if u listen to what he says👍👍👍
Sent from my iPhone using SoCal Jet Boats
-
I gotta hand it to GT, he called on the variables of the equation as I would.
Answer most of those questions and we have a picture.
-
I gotta hand it to GT, he called on the variables of the equation as I would.
Answer most of those questions and we have a picture.
I may have gone a little over the top, but I was trying eat my lunch and realised I forgot a fork, napkin and my iced tea, I had a salad and the dressing decided to somehow get on my pants.
Lol
Another thing to add.
My grandfather always said "brand new" is just another way of saying "unproven".
You have no idea how awesome that statement is until you think about it for a minute.
Lol
GT
-
It sounds more like timing. Your points and mechanical advance might be hanging up. BBO's like about 30* on the average total advance.
-
If he has the old coil I'd try that first. If not that, then the condensor (what's that???). And like GT said, verify voltage at the coil while running.
-
Also, verify that your coil polarity is correct.
-
I have even seen new valve springs that were not set up right, or for the correct application. = Valve float.
-
Which carburetor?
Your fuel test is worthless (sorry).
What fuel pump?
When you say sputters, how? Carburetor, exhaust?
Just misses?
What exhaust?
How are you cooling it?
Compression test?
Timing test is worthless too... What is the timing at over 2,500rpm?
Vacuum advance?
Why points?
How much voltage on the coil with the engine running? What coil? ....
Sorry. Had to.
GT
I'm just catching up on this thread.
GT Jets, I hope you're having your BP issues checked by a medical professional. If not, I am glad, disregard this.
I may have gone a little over the top, but I was trying eat my lunch and realised I forgot a fork, napkin and my iced tea, I had a salad and the dressing decided to somehow get on my pants.
Lol
Another thing to add.
My grandfather always said "brand new" is just another way of saying "unproven".
You have no idea how awesome that statement is until you think about it for a minute.
Lol
GT
-
I'm just catching up on this thread.
GT Jets, I hope you're having your BP issues checked by a medical professional. If not, I am glad, disregard this.
Other than drowning on stupid and lazy at work, I'm cool. Lol
No medical issues here (at least that I'm aware of. )..
GT
-
Platiunum plugs are not what you need in the olds...try using the autolite AR-72 or 73. also I would goto an HEI ignition...do that make sure youve got it timed correctly...if it continues youve got a carb issue in my opinion... keep us updated...
-
Platiunum plugs are not what you need in the olds...try using the autolite AR-72 or 73. also I would goto an HEI ignition...do that make sure youve got it timed correctly...if it continues youve got a carb issue in my opinion... keep us updated...
No Autolites in a Oldsmobile lol... It's not a ford
Sent from my iPhone using SoCal Jet Boats
-
No Autolites in a Oldsmobile lol... It's not a ford
Sent from my iPhone using SoCal Jet Boats
It for sure isnt a Ford. Lol
-
So I rebuilt my 455 olds and got it back in the boat, but around 4k rpm it sputters. It has a brand new edelbrock 750, all new valves, valve guides, and springs, offy tunnel ram, newer holley fuel pump, new coil, mallory single point distributor, brand new autolite platinum spark plugs. Any help would be appreciated
I hope all this advice answers your questions.
-
If you havent tried the autolite ar72 or 3 in your olds youre short changing yourself...ford gets lucky every once in awile and makes something worth a shit LMFAO!!
-
If you havent tried the autolite ar72 or 3 in your olds youre short changing yourself...ford gets lucky every once in awile and makes something worth a shit LMFAO!!
Except Ford has absolutely nothing to do with Autolite.
You are thinking Motorcraft.
Autolite is Fram garbage and I wouldn't run them in a lawnmower.
JMHO, you should be using a plated plug.
Nippon Denso, NGK, Campion, Marine AC Delco, just to name a few...
They won't rust like a standard plug.
JMO
-
Which carburetor?
Your fuel test is worthless (sorry).
What fuel pump?
When you say sputters, how? Carburetor, exhaust?
Just misses?
What exhaust?
How are you cooling it?
Compression test?
Timing test is worthless too... What is the timing at over 2,500rpm?
Vacuum advance?
Why points?
How much voltage on the coil with the engine running? What coil? ....
Sorry. Had to.
GT
Thanks for all the advice everyone. And sorry for the late reply, I've been busy with work. Anyways I ordered a mallory unilite electronic distributor and put that on and a new alternator since the old one was bad, and I still had the sputtering issue. So I threw on an old holley 600 cfm I had laying in the garage (looks like it was pulled out of the ocean it was so dirty) and it ran great on the hose. So I took it out and ran the boat in the water for awhile and it did good but still sputtered a bit once the engine had warmed up. And by sputter I mean when I get on the gas it hesitates and doesnt pick up speed. And to answer a few of your questions GT; the exhaust I have is Hardin logs and snails, 150 compression in all cylinders, and the coil is a mallory electronic ignition coil. That's all the answers I have as of now. Thanks for all the advice and anymore advice will be appreciated. And another thing, I don't know if I should get the holley 600 rebuilt or if the issue could be something else? Thanks in advance
-
I also forgot to mention that I have a really bad exhaust leak at the flange that bolts to the head, does anyone know if I can get a thicker gasket or double up on gaskets? Or maybe the flange on the exhaust is bad?
-
I also forgot to mention that I have a really bad exhaust leak at the flange that bolts to the head, does anyone know if I can get a thicker gasket or double up on gaskets? Or maybe the flange on the exhaust is bad?
Have them milled flat and use high temp rtv, I have had good luck with Ultra Copper.
-
Ditch the mallory single point and go hei or electronic,had the same problem years ago with a dual point mallory,it was on a bbc 461, I know it's not the same motor but symptoms are similiar
X2 on that, had the same problem and went to HEI and cleared it up
Sent from my iPhone using SoCal Jet Boats