Everything done but low rpm at WOT. Distributor spring?

[jimmbo]

I am referring to the Jetting, Accelerator Pump Circuits, Power Circuit. You know the stuff that is a bit harder to see.
Many a used Carb for sale has been rendered useless, by someone who read a HotRod Magazine Tip, or watched some Flunky on YouTube making "Magical Improvements" to these Carbs

 

[Scott Danforth]

All of which can be fixed for less than $30. Then again, I have $500 worth of Holley parts and gaskets in my tuning kit

 

[jimmbo]

Most people don't have a Warehouse of Holley Parts, nor do they have the Info/build sheet as to how the Carb was when it was taken Out-of-the-box.

 

[Scott Danforth]

Most people don't have a Warehouse of Holley Parts, nor do they have the Info/build sheet as to how the Carb was when it was taken Out-of-the-box.

That info is on the Holley site

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://documents.holley.com/techlibrary_carb_numerical_listing.pdf&ved=2ahUKEwj2u8XH1tqAAxXMSTABHaYbB6cQFnoECB0QAQ&usg=AOvVaw1UziVPwG2-N82hs9EiLZMZ

 

[Lou C]

It’s also the old time is money equation. Buy the right thing in the first place & you’ll be better off…so if you have to wait for that carb it might be worth it!

 

[dubs283]

Most people don't have a Warehouse of Holley Parts

But holley does, and they're all for sale. I've never had an issue finding oem parts for holleys, online or locally

Genuine holley rebuild kits come with a plethora of info on rebuild specs for a huge range of carburetors. Schematics, parts lists, tuning specs/procedures, etc...

 

[Lou C]

True, Holley parts are everywhere I could get anything I need for one at a local speed shop here in Long Island. My Quadrajet stuff I get from Cliffs High Performance Quadrajets, Mike’s Carburetor Parts and Quadrajet Power.
The classic car resto industry has kept parts demand for Quadrajet parts high since it came on just about every V8 they sold from 1966-1986 or so. Holleys came on some of the higher performance variants of the muscle cars GM built but standard versions nearly always had a Quadrajet.

 

[VancouverBoat]

You can try calling Holley & see if they have any updated info on that, and also check with resellers like Summit Racing & Jegs to see if they might have any in stock. In the meantime start inspecting all the electrical accessories on the engine for J1171 stamps or labels. If you’re going to keep the boat I would certainly want to know that it was as safe as it should be. Gas inboards are nothing to take likely.
Even fuses used in a closed gas engine compartment are different. Blade type fuses used in a closed engine compartment with gas engines should be ATC fuses not ATO. On an ATC fuse the area where the actual fusible section is located is sealed in the plastic matrix. The ATO fuse is open, and fumes could reach that area & get ignited because when the fuse blows the fuse arcs. So if you have an auto bilge switch with a fuse in the engine compartment use an ATC fuse. A little known factoid about fuses….

Thanks, will do.

 

[VancouverBoat]

Guys I added a fuel pressure gauge just before carb and at first I got 5 psi which is in range. Now I get 3 when cold and 4 then5 when warm . I am guessing this is going to be my issue.fuel pressure. Of course I thought that was ok before but after going back it look like that might be an the issue. I hope so so I can fix it. It seems like it is intermittent. So.times 5 (in range) and sometimes low. It seems to come up when warm. Is that weird? I know I still have to check with load wot. I will.

 

[jimmbo]

Guys I added a fuel pressure gauge just before carb and at first I got 5 psi which is in range. Now I get 3 when cold and 4 when warm . I am guessing this is going to be my issue.fuel pressure. Of course I thought that was ok before but after going back it look like that might be an the issue. I hope so.

Most carbs run fine in the 3 to 5 psi range. Pressure is only part, Volume is the other. If the pressure is dropping, there may be a restriction upstream of the fuel pump

 

[VancouverBoat]

Most carbs run fine in the 3 to 5 psi range. Pressure is only part, Volume is the other. If the pressure is dropping, there may be a restriction upstream of the fuel pump

I took out the anti-siphon valve and it is working and looks brand new. no restriction in inlet tube.

 

[jimmbo]

There still is the Pickup in the Tank, that can get clogged. I've seen what looks like Gelatin on the Inlet Screen/Sock/Strainer

 

[Scott Danforth]

If you are getting 3-5 psi at the carb with the motor at WOT under load, there is no restrictions in the fuel inlet

 

[VancouverBoat]

If you are getting 3-5 psi at the carb with the motor at WOT under load, there is no restrictions in the fuel inlet

So it is ok to be as low as 3? The reference sheet for the OMC 460 for that year 1989 says 5-6psi

 

[Lou C]

Might also want to check you total timing advance; here are the specs from my OMC shop manual.

 

[Scott Danforth]

So it is ok to be as low as 3? The reference sheet for the OMC 460 for that year 1989 says 5-6psi

as long as your 3psi is at WOT while under load, you are fine. holley carb will function properly as low as 2 psi and as high as 7 psi

 

[VancouverBoat]

as long as your 3psi is at WOT while under load, you are fine. holley carb will function properly as low as 2 psi and as high as 7 psi

Does this look like fuel pressure is ok at WOT?. Please note the fuel pressure gauge. https://photos.app.goo.gl/hzxaonxRYfu1k9nJ9 Still only got to 3500 rpms on that... seems to go between 3 and 2 Here is another bit longer video https://photos.app.goo.gl/Ad1RsKiowqUdqB9s9

 

[Scott Danforth]

your videos are blurry and cant read the numbers

just post the numbers

also, I dont have sound on my home computer. so I cant tell if you took the boat out and did a hole-shot (full prop load) to read the fuel pressure.

dropping to 2 psi and you will have an issue as you probably wont open the floats.

you are still running the mechanical fuel pump, correct

I would run the motor from a remote fuel tank and test fuel pressure to isolate if you have a pump problem, or a fuel tank pickup/anti-siphon problem

 

[VancouverBoat]

your videos are blurry and cant read the numbers

just post the numbers

also, I dont have sound on my home computer. so I cant tell if you took the boat out and did a hole-shot (full prop load) to read the fuel pressure.

dropping to 2 psi and you will have an issue as you probably wont open the floats.

you are still running the mechanical fuel pump, correct

I would run the motor from a remote fuel tank and test fuel pressure to isolate if you have a pump problem, or a fuel tank pickup/anti-siphon problem

Yes, I did these videos out on the water and went to full load WOT. For me that is 3500 rpm. Yes mecahnical pump. The rpms did and do stay steady at whatever rpm I try, so it is not like the carb is bogging or waivering. On the first one the reading was 3 and then at WOT it was flickering between 2 and 3. On the 2nd it started at 4 and then went down to 3 and then flickered between 2 and 3. A post above I was told that anything between 2 and 7 is ok, so I am not sure if this is acceptable. I have checked the pickup and anti-siphon and they are ok.

 

[drewm3i]

What is the coil voltage? You could have weak spark.