[george kujanski]

So i go to start the boat......a squirt of fuel and it starts right up ...for about 5 seconds, then no starting.

Took a look at the carb and it's flooding.
Loosen the fuel fitting to stop the flooding. Ok, so it's the inlet valve, right?

order a new kit from mercruiser and it comes with an inlet i never saw before. instead of the "needle:" valve with the little hanger on it (so the float would open the valve), it's got a valve that has a recess drilling into the valve body on the float side into which a tiny spring seems to fit and then a tiny plunger goes into that. Looks like the float tongue presses against the little plunger, compressing the little spring first, then the needle moves fully once the tiny spring bottoms. i figure it's used such that the tiny spring applies a light closing force on the needle as the float comes up.

What the hell, just trying to blow into the inlet with the cover upside down (valve closed), i can't blow any air. So I figure the pump pressure should open it, right?

reassemble, try to start, if I add some fuel it pops. Try again, nada, carb throat is dry even pumping.

Valve stuck closed?

The kit doesn't come with any instructions, setting, either.

Close up shop for the day.....

Anyone know how the new valve assy is supposed to work?

George

[steve25]

Well what is the carb your talking about here, a Q jet?

[carbking]

George - spring-loaded valves have been around for at least 90 years for marine operation.

However, the float adjustment is different for the spring-loaded valve. When setting the float, do not press against the spring.

Give Mercruiser a call, and see if you can get some specs for your model.

Jon

[george kujanski]

Hey gang...it's a Rochester 2GC, forgot to mention. Jon, just how is this supposed to work, anyway? Should i be able to blow thru the fuel inlet to unseat the valve? That's not happening unless my lungs can't develop enuf pressure. When setting the float all i did was turn it upside down with the weight of the float pressing down on the valve.

George

[Cliff R]

NOT a fan of those self-contained fuel inlet valves. I tested them EXTENSIVELY when I first went full time into building Q-jets many years ago. They did NOT make the grade or work as advertised. I would install a conventional N/S assembly instead and move on.......FWIW....

[steve25]

Unlike a Q-jet the float in the 2bb hangs off the air horn.
It’s not in the throttle bore casting as in a Q-jet.

When you do the blow thru test on this type of set up the reverse of the Q-jet should be done.

With the air horn sitting in it’s up right position is when the needle and seat are separatated.

[george kujanski]

Cliff: that's what I will do if I can't get fuel into the carb. Without the pull down clip, the needle seems to stick closed. Along with what Jon says, I'm wondering what it the purpose of the spring design for marine use?

George

[johnta1]

I would think it is to keep the float from bouncing open with rough waters or other actions. (lot more movements in a boat compared to car)

[mgarblik]

Originally Posted by george kujanski

Cliff: that's what I will do if I can't get fuel into the carb. Without the pull down clip, the needle seems to stick closed. Along with what Jon says, I'm wondering what it the purpose of the spring design for marine use?

George

It is supposed to act like a tiny shock absorber for marine and off-road use. Not sure why yours seems to be sticking. I can see when working properly, it may provide a more stable fuel level in the bowl of a boat carb. But it has to work. They are designed to work wet, so see if you can duplicate that.

[carbking]

Originally Posted by george kujanski

Hey gang...it's a Rochester 2GC, forgot to mention. Jon, just how is this supposed to work, anyway? Should i be able to blow thru the fuel inlet to unseat the valve? That's not happening unless my lungs can't develop enuf pressure. When setting the float all i did was turn it upside down with the weight of the float pressing down on the valve.

George

George - this is the proper procedure.

Maybe you are not blessed with as much "hot air" as others

The spring-loaded fuel valve was developed for two reasons for use in both marine and off-road applications:

(1) As mentioned by others, to maintain a more stable fuel level in the bowl
(2) To eliminate damage to the float itself from shocks of wave movement or large bumps (maybe I need to add them to my personal road vehicles, I can fish in local potholes after a good rain! ).

It may be that there is a sharp edge on the seat orifice caused by broaching that is causing the valve to hang. Quality control on some products is not what it used to be.

If you don't do a lot of wake-crashing, perhaps Cliff's idea of using a conventional fuel valve is the solution.

Jon

[george kujanski]

Thanks, guys. I was thinking it may have something to do with a "softer" closing of the valve. It is a Mercruiser kit so i assume they know what they are doing, marine-wise. No instructions in the kit tho, they provide a ruler but no other instructions............ like how to assemble the 3-piece valve. that's just poor. I had to guess, like what is this tiny spring and plunger for? The previous assy had the std. valve, from a Sierra kit i used years ago when the valve stuck open

George

[Cliff R]

I don't use or like any of those self-contained inlet valves as mentioned and have had perfect success with the conventional variety.

In actual use the float has enough bouyancy to keep the needle pinned hard against the seat that those added springs are not needed. I would NOT use a brass float in it however, get the full size nitrophyl instead. I've had ZERO success with brass floats since they went to Taiwan for them a little over 20 years ago.

I actually build and have built a LOT of Marine carburetors, Q-jets, 2JET and those POS Webber/Edelbrock AFB clones that started showing up on Marine V-8 engines when they phased out Q-jets in the 1990's. I will say this when it comes to Marine carburetors, pay very close attention to the float levels listed for them. Each part number has a SPECIFIC float level and for a good reason. Often the engines are canted in Marine applications, so much so some even use a wedge plate under the carb to level them out some. You absoutely MUST use the correct size fuel inlet seat. OEM style float, and set it exactly to specs or it simply will not work.

I just finished up two Marine Q-jets for a customer. He went thru over 2 years of "drama" with them, plus invested well over $1000 before he hired me to correct the issues. They are for an off-shore boat powered by two 350 SBC engines. First they were built by a Marine mechanic well known for doing them, they didn't work for chit. So he went on-line and ended up with two I-5 Marine "replacement carbs" which were WORST than the "rebuilt" original units. He sent the original units here. They had automotive accl pumps in them plus the WRONG N/S assemblies (WAY too small) and brass floats (not bouyant enough for effective fuel control).

I cleaned them up, installed the correct high-flow N/S assemblies, floats, and Marine length accl pumps. He tested them extensively, below is a part of the email which relates to using the correct floats and N/S assemblies in them:

Here we go:

"At idle on the way out-

It will idle at 600 rpms in gear now, very smooth with no missing or rpm change. Just rock solid. (This is a big change, in the past it would not idle this slow and the engines would randomly misfire.

Cruising speed-

Once again, very smooth and sounds better. I can’t tell if the boat is faster.

Now the engines are burning a total of 19.5 gallons an hour. This is very close to what the engine manual states it will burn.

Wide open throttle-

Here is where I am seeing another very big improvement. Before these carbs were rebuilt I could only get the engines up to 3800 RPMs. One or the other engine would stumble and the rpms would drop to about 2500 rpm. Speed was around 25 knots. The I-5 carbs were worse. They would stumble at 3600 rpm and then drop to about 2300 rpm. Top speed was a little less.

Now with the rebuilt carbs the engines turn 4600 RPM, 29 knots boat speed. 200 RPM higher than the 4400 rpms the manual recommends and 800 + RPMs higher then the old carbs would do. (Now I can re-prop the boat and get the WOT RPM to 4400 where the should be. The props are under pitched compared to what the boat originally came with and it shows in these numbers) By the way, the original sales article states the boat went about 1 knot faster than I’m going now. When I did this test the boat had full water and full tanks, plus all the typical gear I carry, which I know is more weight than when they ran the test."


Moral of the story here. You MUST use Marine type/grade parts in Marine carburetors. Sadly most of the "Marine" rebuild kits are no longer spec'd with the correct N/S assemblies and much shorter Marine length accl pumps. Plus the accl pump seals are NOT ethanol compatible even if they are "blue" in color. It's a sad state of affairs when it comes to this topic, but outsourcing and companies making and selling parts have been forced to consolidate, find cheaper components and put together more "one size fits all" kits to survive in this industry.......FWIW.......

[Cliff R]

Ya ya, I know this isnt exactly "Pontiac related", but using the correct parts in anything you are working on is the only path to success with this sort of thing. NEVER assume what you are buying is OEM quality or even correct these days. WAY too much outsourcing and substituting inferior and incorrect components with just about everything we do related to this hobby.

Feel free to transfer this thread to Members Helping Members where it probably should be anyhow.......

[george kujanski]

Cliff and Jon and others....thanks for your responses and expertise.

George

[Ram Air IV Jack]

Originally Posted by Cliff R

Ya ya, I know this isnt exactly "Pontiac related", but using the correct parts in anything you are working on is the only path to success with this sort of thing. NEVER assume what you are buying is OEM quality or even correct these days. WAY too much outsourcing and substituting inferior and incorrect components with just about everything we do related to this hobby.

Feel free to transfer this thread to Members Helping Members where it probably should be anyhow.......

Cliff, I know this very well from when you rebuilt my Qjet several years ago. My Qjet had been rebuilt by Brads Carburetor Shop in Ontario California, now defunct, years before you got ahold of it. Brads had a good reputation but when you received the carburetor because of the stripped-out fuel inlet, I was horrified on what you found. The primary jets had worn oblong because there was no spring attachment on the primary metering rods to power piston, so the vibration caused this wear. Further, the spring used for the power piston, using your words, looked like it came from a ball point pen. There were other adjustment issues as well and your service did cost me more than I paid to have it rebuilt twice. However, the car has NEVER run better or started as quickly as it does now. So many shops today cut corners and put half arse parts in these carbs while the customer pays good money thinking the service provided is correct. It is spooky to think about and it seems many are victims of poor parts and service at one time or another.

[carbking]

Originally Posted by Ram Air IV Jack

Cliff, I know this very well from when you rebuilt my Qjet several years ago. My Qjet had been rebuilt by Brads Carburetor Shop in Ontario California, now defunct, years before you got ahold of it. Brads had a good reputation but when you received the carburetor because of the stripped-out fuel inlet, I was horrified on what you found. The primary jets had worn oblong because there was no spring attachment on the primary metering rods to power piston, so the vibration caused this wear. Further, the spring used for the power piston, using your words, looked like it came from a ball point pen. There were other adjustment issues as well and your service did cost me more than I paid to have it rebuilt twice. However, the car has NEVER run better or started as quickly as it does now. So many shops today cut corners and put half arse parts in these carbs while the customer pays good money thinking the service provided is correct. It is spooky to think about and it seems many are victims of poor parts and service at one time or another.

I quit reading Hot Rod Magazine after the issue with the article advocating replacing the vacuum piston spring in the Corvette 283 2x4 carbs with springs from Paper Mate ball points.

Brad Urban was GOOD! But like many folks that start their own business, employees are often necessary. One of the reasons my business has hired only immediate family members.

Jon

[Cliff R]

I'll also add this little tid-bit here. For decades I've offered the service of installing heli-coils for stripped out inlet threads. I had to stop taking in the entire carb and just the main casting stripped down.

The owners of these carburetors told me that they were "working fine", but when I took them apart they were NOT up to par and many had miltiple issues that needed attention.

So here is the quandrum, IF you install the heli-coil and put it back together knowing it has issues, but the customer said it was working fine, what's going to happen when they get it back?

I'll tell you EXACTLY what's going to happen. You are going to get a call and the owner will say that his carb workied just fine until you touched it, now it doesn't do anything right!........

[Ram Air IV Jack]

Originally Posted by carbking

I quit reading Hot Rod Magazine after the issue with the article advocating replacing the vacuum piston spring in the Corvette 283 2x4 carbs with springs from Paper Mate ball points.

Brad Urban was GOOD! But like many folks that start their own business, employees are often necessary. One of the reasons my business has hired only immediate family members.

Jon

Yes, Brad Urban was good with a solid reputation, and he returned the carb quickly, colored and rebuilt looking like an NOS unit!! It ran well until it began to leak at the fuel inlet and I contacted Cliff. After Cliff got done with it, it never ran better so Urban had to have cut some corners or one of his employees did!!!

[Ram Air IV Jack]

Originally Posted by Cliff R

I'll also add this little tid-bit here. For decades I've offered the service of installing heli-coils for stripped out inlet threads. I had to stop taking in the entire carb and just the main casting stripped down.

The owners of these carburetors told me that they were "working fine", but when I took them apart they were NOT up to par and many had miltiple issues that needed attention.

So here is the quandrum, IF you install the heli-coil and put it back together knowing it has issues, but the customer said it was working fine, what's going to happen when they get it back?

I'll tell you EXACTLY what's going to happen. You are going to get a call and the owner will say that his carb workied just fine until you touched it, now it doesn't do anything right!........

I get that Cliff, but we agreed you would take it apart for an inspection. You called a day or so later and explained the issues with my Qjet. I remember this well and I said put the internals back to factory specs and I'll pay for the entire rebuild. You quoted me a price and I paid extra for you to test the carb as well. It has NEVER run better!!

I can see customers complaining to you as you mentioned after Heili coil repair but unlike some, I understand and followed the instructions you laid out of me. It isn't hard but many people out there can't or won't follow anything believing their way is better! I know you've spoken about this a lot on this forum. That is just some people and there is little you can do if someone doesn't want to listen.