Questions for Makomark

"Hey Makomark,
I read some of

"Hey Makomark,
I read some of your posts for the Q Jet overhauls and I have a couple questions.
I have a 28' Carver (Heavy) with twin SB Crusaders (220).
I got two kits from Cliff and his book.

I can't find the spec's on this carb (17082403)
Looks like this carb is used on both the 305 and 350 SB GM engines?

Here's my questions;

What should the float be set at?
With the 220 SB, do I need the air bypass, or is this a BB deal?

Thanks for your help.

Bob"

"Bob:

I may have the OEM se

"Bob:

I may have the OEM settings sheet at home. If time permits and I find it, I'll amend the info that follows.

The factory merc manual that is available right now shows ALL of their mid-80's Qjets to have a float setting of 15/64th. Mine are set at 3/8". The lower level minimizes the sloshing/dribbling that sometimes occured out of the secondary accelerator wells. You can set it at either level and adjust if necessary. Lowering the fuel level slows the nozzle response a little; I haven't found anybody yet, with a boat, that can notice a difference.

The need for bypass air is identified by your engine's idle characteristics. If you have full control with the idle mixture screws with the recommended idle RPM, additional idle air shouldn't be needed. Adding 0.020" passages won't have much, if any, impact to idle speed.

You can add the passages in the bowl castings and then put a "tiny" hole in the throttle castings while it is apart (if you didn't take good notes before pulling things out). Then, if you need to increse the idle air, you only have to open the holes on the bottom. if you'd rather just pull the air horn, you can take the same approach but put the restriction in the bowl casting. There are a few other approaches, if needed."

"Thanks,
I have both engines

"Thanks,
I have both engines out (overhauled both engines and both transmissions), I am in the process of overhauling the pumps, carbs, starters, alternators and so on. I have not disassembled the carbs yet, maybe next week. Just want to have all my ducks in a row before I start."

the rochester sheet shows thes

the rochester sheet shows these:
float 9/32"
pump setting inner
air valve - 3/4
vac break 27 deg
air valve rod 0.015
sec lockout 0.015
the other values are footnoted as "see marine manufacturer's data" or functionally equivalent words.

Thanks Mark.

Thanks Mark.

Did Cliff tell you what he siz

Did Cliff tell you what he sized the idle tubes at?

"No, I sent in his form with t

"No, I sent in his form with the engine data and the GJet numbers. He wrote back that he had "kits" ready to ship.
My guess is this is a basic set up, as he had them ready made.
Should I sign up for his forum and ask him?
(I did send him an email about the float, and he maintains his 1/4 in setting.)
Maybe I'm getting the parts for his "first recipe" in his book?"

"His kits are custom assembled

"His kits are custom assembled, rumored to be done by his wife, who is also alleged to be a pretty handy "carb machinist". Never met her so can't verify.

Part of the customization is the option (no extra charge) of getting him to size the idle tubes. I guess if you don't know what you need, he derives the data based on decades of empirical data.

As far as the receipe's go, you have the bulk of the parts in the default carb. remember, the main audience in that book is the auto owner. Many of the mods in the book will work in the marine ap but some won't - specifically anything for high (over 5000 rpm) speed operation. Your boat engine won't do it, at least not for long.

If you're used to a standard rebuild kit, you will be in for a surprise when you open the box."

"Mark, your absolutely right.

"Mark, your absolutely right.
I have opened one, and it looks very complete.
I love the kits you get at NAPA, a couple gaskets and maybe the accelerator pump, maybe.
I think I want to build these back to factory settings. The boat ran well all it's life (20 years) at 5000' ASL (Flaming Gorge Lake in Utah). I will be doing the majority of my boating at 5600' ASL (Navajo Lake in NM) or 4200' ASL (Lake Powell)."

"I'm a little concerned wi

"I'm a little concerned with the Qjet casting number. 17082403.
Looking at Cliffs book, I would expect the "0" to be an 8 for marine use!"

I'm in the process of orde

I'm in the process of ordering a new q-jet for the "other" motor.

The one on the starboard is ......17059213.....and I will order the same thing for the port motor and the core I am sending back from the port motor is 17085246

"Don,
I wonder if Rochester e

"Don,
I wonder if Rochester ever made a casting number with "8" for marine?"

"Bob-
The "8" is legi

"Bob-
The "8" is legitimate, it's part of the year encoding....why does it concern you? I've got one with a "9" in that slot and that was new to cliff. I also saw a notice that there was a new thread started on cliff's board with your cast number - take it that was you?

If you are that high up, you may want to consider jet changes, for altitude, if you are concerned about the economy.

On the casting numbers - most everything you will read is automobile specific. Use that info with caution."

"Don-
If they accept the core

"Don-
If they accept the core w/o issue, what will that tell you about their operation?

Where are you getting a "new" one from?

Are you sure it is a RPD casting?"

"Mark,
Yes that is my post at

"Mark,
Yes that is my post at Cliffs site.
I just went down to the garage (kinda a pain, I need to use my back brace just to walk down the steps). Anyway, took a look at both carbs, they have the green shafts and the only port on them is for the "sight tube", so I guess I'll quite wining about the numbers and just get to it.
I think I will have Cliff send me a couple sets of jets. I'm sure I will be running on the rich side."

"Mark...
I have been having c

"Mark...
I have been having conversations with the fellow at FLYING FISH Carbs, (Florida) and they will not be giving me a full core refund as the return is apparently not acceptable as a full marine modified carb.
With respect to the casting as to whether it is RPD or not...how would I know?

The old carb is now sitting on my desk, and I am open to any source/suggestions as to where I will get a fair deal and the right carb.

The reason I went back to the same company is that the carb they sent up in the spring of 2008 has the engine just purring and the one on the port engine just seems to be real cranky..no matter what my marine mechanic does."

"ROCHESTER is cast into the si

"ROCHESTER is cast into the side of the bowl, not too far from the model number/date code stamps.

Will they not give you any core credit or just partial? Due to different number?

What was requested & what was sent back as far as the carb number on the last transaction?

If you are happy with the product & service, no reason to change. If looking for alternatives, you could mod the 'bad' one to behave like the 'good' one. You could also opt to have another do it. Personally, I believe fixing what you have is normally the best approach."

"The one that is really good h

"The one that is really good has the following numbers.....
17059213 and beside those numbers is ....1509CBL
I will look for the words Rochester on it tomorrow.

Partial Core Credit only

The one I am sending back does have the words "Rochester Quadra-jet."

The last time I dealt with the fellows they sent me that carb as above.I just requested a Rochester quadra jet for a small block Chevy (350CID) and they knew it was a marine application. They're stock is a Y40-1E which is a side mount gas entry with electric choke. They looked up the sales slip of the last carb they sent and I stated that I wanted the identical carb this time ...I have not made an order yet.

Apparently the carb I sent back last year was a modified carb for marine but was originally off an International truck...however they did give me full core return credit.

I believe in fixin what I have too but one thing I am not proficient in is carbs but I do have an excellent mechanic and he says he just can't get the d%^&*# carb to run properly..even after a rebuild and I have a lot of faith in him, (worked on all my engines for 13 years) so to save the hassle I felt it would be prudent to just spring for another carb.

It should be pointed out that all my ignition wires were new last year, Dist cap changed every two years and plugs changed every Spring. All cylinders have excellent compression.

C U tomorrow."

"Bob - found my old service bu

"Bob - found my old service bulletin stash. For 'higher elevations', they only suggest changing the timing (+2 deg) and secondary rods (leaner).

I'd suspect you could probably also go down a size (or two) in the primary w/o any consequences...like other changes, need to pay attention afterwards to assess the 'goodness' of the change."

"Thanks Mark,
I made a note t

"Thanks Mark,
I made a note to myself to add 2 Deg. to my timing.
On the secondary rods, can these be adjusted (lowered into the jets) or do I need to buy some longer ones.
I will add this question to Cliffs site as well.

Bob"

"Mark.

Yesterday..<font col

"Mark.

Yesterday..<font color=""0000ff"">The one that is really good has the following numbers.....
17059213 and beside those numbers is ....1509CBL
I will look for the words Rochester on it tomorrow.</font>

<font color=""000000"">I looked today and the Carb has ROCHESTER QUADRA JET on the body</font>"

"Bob:

you can change the ha

"Bob:

you can change the hanger, lower, but that is more of a fine tuning method. You would want a thicker tapered pair than what you have. Cliff may be able to make you some if you let him know what you have now.

Don: at least it is a real one. I don't have much to verify if the casting was OEM marine."