Replacement Carburetor for 85 and 87 SN

trice wrote: Not satisfied with the starting, idle quality, and throttle response from the original equipment Holley carburetor. The list number on the 87 is 50419. Any recommendations on a replacement? A good friend has an 85 with the same issues. Thanks

Tom, if you hang on a while, Jonny Quest aka JQ aka Jonny D QuickFuel will be back to give you his totally biased glowing recommendation for a Quick Fuel M-600

A lot of people have used them with good results. They have more adjustment capability than the typical marine Holley. That means there are more ways to screw it up too if you're a "tweaker"

If you're replacing something old that doesn't work right any more, a new Holley or Quick Fuel is bound to be an improvement but a good rebuild on the Holley might cure your issues too for a lot less money.

Jonny Quest wrote: To get the proper rebuild kit, you need the carburetor number. The carb list number should be hand-stamped on the front of the choke tower, to the right of the vent tube. Generally, the list number is 4 - 6 digits long and may have "suffix" numbers also. JQ

trice wrote: The list number on the 87 is 50419.

It might even resemble the list number he gave in his first post

I Love You Keno.

Great list of options JQ, thanks!!

I like the Quick Fuel option the best. I have one on my Road Runner and love it! The decision now is 600 vacuum or 650 mechanical. I’m not sure what CFM the original HOLLEY is? I think it’s a 600. I know it’s a vacuum secondary w/electric choke. Fuel line plumbing is another consideration. The 600 is a single inlet like the original and looks easier to connect. Also wondering if the original spark arrestor will fit the QF?

Thanks Keno. I’m interested to her why JQ went to a 650 mechanical. The 600 vacuum seems like the closer replacement for a stock 351W.

trice wrote: Thanks Keno. I’m interested to her why JQ went to a 650 mechanical. The 600 vacuum seems like a closer replacement for a stock 351W.

The 4160 Holley was OEM equipment on your 351W. As such, the QF M-600 is closer to the 4160 -- no doubt. However, I like the 4150 design a bit better than the 4160.

As for mechanical vs. vacuum secondaries, I like the mechanical setup. The QF carb comes with several linkage options that will open the secondaries at different throttle positions.

My M-650 is set up so that the secondaries kick in at about 1/3 throttle, which works for me and the group of skiers I pull. Hole-shot is very strong and midrange RPM (2,500 - 4,500) is REALLY strong. I replaced the stock cast iron intake with an Edelbrock Performer RPM and I felt that the M-650 was a better match. Based on performance, I feel that I made a good decision.

I also love to work on engines, so sometimes "upgrades" may not be needed, but simply fun to do. Did the M-600 run well? Yes. Does the M-650 run better? I think so, but can't really prove it as it is based on a totally subjective "feel".

The photo below shows my fuel delivery:


JQ

Aeroquip does make a USCG approved hose , but that ain't it in the picture

Here's a link below

link

Trice:

My setup has no fuel filter between the mechanical fuel pump and carby inlet. I have a fuel filter / water separator between the fuel tank and the fuel pump. At the top right-hand of the photo, you can see the clear tubing attached to the spark arrestor. That is the visual safety tubing from the fuel pump.

The original spark arrestor didn't quite fit on the original M-600 carb. My engine was originally the throttle-body fuel injection and the spark arrestor may have been a bit different than yours. As such, the original spark arrestor unit wouldn't lay flat on the carb flange -- due to the float adjustment hardware on the QF carb (not on the Holley). So, I went with the K&N unit shown in the photo. The K&N unit has options for a breather hose and fuel safety hose attachments. Another reason I went with the K&N spark arrestor is that it is larger in diameter and thinner than the stock unit. As mentioned above, this engine is sporting an Edelbrock Performer RPM manifold -- which is a bit taller than the stock cast iron unit. This whole unit fits under the engine cover with about 1 inch to spare.

Fuel inlet. The M-600 is set up just like your 4160 (port side fuel inlet) so it should bolt right up to the existing fuel line. The M-650 has the fuel inlet on the starboard side of the carby and therefore required a new fuel line. The high-pressure, racing stainless steel braided fuel line shown may not be USCG rated, but it is approved by the Utah Zepplin Spotting Club. For a bonus point, some of the fittings are RED.

JQ

From KENO:
I seem to think that JQ used some Sierra 18-8115 fuel line when he had the M-600.

I bought the Sierra 18-8115 fuel against my better judgment -- I've not had good luck with the Sierra brand. The line was semi-flexible and kinked during installation. That's when I went to the local hydraulic / hose shop and started down the "dark side" path of braided stainless-steel high-pressure, non-USCG approved fuel lines. My braided stainless-steel line is far superior to the POS Sierra line that was USCG approved.

I had 2 of the local "Fish Cops" on my boat this year and they had nothing but praises for the engine and condition of the boat. I guess the braided stainless-steel line must be OK.

JQ

Geez KENO...who peed in your Cheerios this morning?

DISCLAIMER (for KENO's blood pressure)

WARNING!! ONLY USE USCG APPROVED PARTS (your boat can burn to the waterline within seconds if you don't)

I may or may not follow this advice on fuel lines.

Yup...I sold the flexible Sierra fuel line. I also sold the metal pre-formed fuel line. And, no, my conversation with the buyer did not include my bias against Sierra products as this unit carries the USCG stamp of approval and any contrary opinion is clearly unfounded and therefore should be disregarded. And to put everyone's mind at ease, I did not attempt to convince the buyer to utilize illegal and dangerous non-USCG approved parts, saving himself from an imminent deflagration.

In my opinion, the lack of a USCG approved "stamp" does not automatically mean that something does not meet the standards, it simply means that it has not been tested and approved by the USCG.

** NOTICE **

Parting out 1994 SNOB as it is too dangerous to operate in its current non-USCG state.

Bottom line is no one paid off a government entity to get it approved. AN hose is good enough for the FAA but not good enough for the Coast Guard- every boat must have a life vest, but aircraft are not required to have parachutes. On that note every fuel hose on a GT40 has a coast guard approval tag with the approval number on it except the crossover hose for the fuel rails but that's ok it's only at full rail pressure and mounted at the top front of the engine so it will only spray half the engine

It has been years since I worked with a Rubber company that made USCG approved hose but what I remember is our hose had to meet an approved test and it had to do with exposure to fire. It had to contain the fuel under pressure while exposed to a fire for a certain number of minutes, sorry I do not remember the time frame. The idea was if your fuel hose did not burn through right away in a fire it would give the operator and guests time to leave the boat before pressurized fuel hit the fire.
I am thinking it was something like 2.5 minutes at a certain temperature or in open flame exposure.
There is a reason this type hose is so danged expensive and it may save your life someday.
Be careful, some of the stuff coming in from overseas is questionable. No Agency is actually stopping freight coming in to see if it actually meets the standard stamped on the hose. I would stick with one of the known vendors.
In the old days that was Gates, Dayco and Goodyear, today there are a few more players.
Or just install metal lines and forget about it.
I did not think about it before now but PCM did use a flexible stainless hose on the return line on my GT40, no idea if it meets USCG approval. I would think so as PCM has been at this a long time.

Jonny Quest wrote: KENO wrote: I guess I'll go out and starting with some automotive parts, make my own marine carburetor, marine starter, marine distributor and marine fuel line tomorrow since I now know it's OK to do that since I can determine that they meet or exceed USCG regs all by myself.. It shouldn't be very hard The next day I'll tackle an alternator. Give me a call and I'll come help out. I've got some experience along those lines. I'll bring the AN fittings. JQ

OK, we'll have some good ol' fashioned fun

I checked and I have some RED paint

Despite appearing to kink more easily than I’d like, I have not found the “POS” Sierra to actually restrict fuel flow. I’ve been running mine for years on the BFN that has spun 6k rpm on occasion. Currently working just fine on the 5200rpm detuned version. I’ll gladly take the 50% discount even if the kinking wasn’t mentioned beforehand.

For a cheap (and USCG approved) setup, there are dual taper to barb fittings available for $3 and a length of A1 hose is pretty economical.