full spectrum carbs and popoff

[Flash-FX]

I don't know I'm still at 90 %. If I ever get that last 10 % and find out I will post it here so everyone will tell me I'm wrong.

I'm close to those same #'s. That last 10% is the tough part.

Here's a couple of pictures just to prove that I don't know what's going on yet...Who else would cut a hole in the side of a 2yr boat just to get at the carbs? LOL...Back before the cool 2 piece Boyesen and R&D dual manifolds, It would take a good hour+ to do a jet/pop-off change (duals) on the FX (there's no room in there, even with custom offset wrenches). I even welded a cable stop on the front of the manifold so the dual carbs could be run with the pump sides in. The pictures show the single 46mm setup, also spun around. I could do a jet change in about 10 min on the single.

The round patch is a cover where a Racepak II used to be before it turned into a aquarium. Before that died, It allowed me to dial in the top end perfect. You could set both carbs to run all day WOT @ 1150 or whatever degrees...and the sales guy told me it was waterproof....LOL...

just to know for sure,I pulled the carbs off the stroker and put them on a ported 701 I have.At first they were still muddin along in 1/3 range,but I kept moving the pilot screw in adjusting the pop off slightly with bending the t bar.I forgot to bring a pop off guage with me,but I really smoothed out the 1/4 to 1/3 slow accel and cruise areas alot,I was close to getting it perfect

The cold water seems to help make it run a little leaner (crisper).

 

[Matt_E]

That's one hell of a flame arrestor.

 

[egbrig]

As much as I hate the idea of cutting a hole in the side of the hull, that would make everyones day that much easier. Very cool.

 

[masterblaster]

flash, I always thought that not having the jets facing in where they are exposed to the strongest signal made the larger carbs harder to tune. I almost bought one of those race packs.Did you use it with dual egts so you could get each carb perfect? It would be nice if the leads were long enough to put the unit up on the pole where it would stay dry,at least for tuning then remove it.I dont think I need it that perfect though,a tach will suffice. Is that some kind of thermostat on your water line? I almost bought something like that from Art for winter rides.Thats funny with the hole in the side the boat,I recently bought 2 r&d 2 piece manis angled spacers to run the moto tas 2 reeds,it sure is nice pullin carbs and jettin that fast

I also have very small water restrictors in my ski so within a few min it s up to usual summer water motor temps. I found that decreasing the pop off and turning in the low speed screw really helped that 1/3 throttle range. Im going back out today now that I fixed the ski and see if I can get it perfect.

 

[Flash-FX]

That's one hell of a flame arrestor.

Vintage pix from the 90's are great...aren't they. lol That was a piece of K&N wrap around off road filter that actually worked. Water would hit the large pores of the foam,and drip off.

flash, I always thought that not having the jets facing in where they are exposed to the strongest signal made the larger carbs harder to tune. I almost bought one of those race packs.Did you use it with dual egts so you could get each carb perfect? It would be nice if the leads were long enough to put the unit up on the pole where it would stay dry,at least for tuning then remove it.I dont think I need it that perfect though,a tach will suffice. Is that some kind of thermostat on your water line? I almost bought something like that from Art for winter rides.Thats funny with the hole in the side the boat,I recently bought 2 r&d 2 piece manis angled spacers to run the moto tas 2 reeds,it sure is nice pullin carbs and jettin that fast. I also have very small water restrictors in my ski so within a few min it s up to usual summer water motor temps. I found that decreasing the pop off and turning in the low speed screw really helped that 1/3 throttle range. Im going back out today now that I fixed the ski and see if I can get it perfect.

I've heard all different thoughts about which way to run carbs (pumps @ the front or back), but in that case of tuning, I don't think it's a big deal. Plus I could not never feel a difference anyway.
Yea, The Racepak was cool. I had 2 temp probes set in the B pipe manifold. Best of all, it was easy to use. It also had a "record" mode that recorded a run, temps,rpm....watch the playback, great for dialing you high speed circut. NO guessing. If that thing (or something like it) was available and really waterproof, I'd buy one again. Awesome tuning tool, NO meltdowns.

The quick dis-connects aid in doing pop-off tests. They are the kind with internal shutoff. When you disconnect the return line, it's plugged. Now, connect the fuel line supply to the air line (with the 0-30 gauge in line), and do your test. I use a Park bike pump for the air.

Hey now...you know that low speed screw is used for ONLY setting the idle.....no cheating now.

 

[2XLR8]

flash,

I also have very small water restrictors in my ski so within a few min it s up to usual summer water motor temps. I found that decreasing the pop off and turning in the low speed screw really helped that 1/3 throttle range. Im going back out today now that I fixed the ski and see if I can get it perfect.

I am willing to bet that restricting the water raised the water pressure and that is helping you tune the carbs better. Those pipe screws can be day and night difference when it comes to dialing in a set of carbs specially on a modified engine. I am sure you knew that though.
Just putting in some of my 90 %.

 

[kevbo]

What's your solution to not have that 1/3-1/4 "muddy spot"? An accelerator pump.

 

[masterblaster]

flash,thermostat for the fuel lines...lol I was talking bout that round silver thing just under the quick connects on the red plastic thing? what is that?

So I think I got this figured out. Ed makes a big deal out of not having the main screw open more than a half turn,better metering circuit.almost everyone is running his recomend jets on mains being 135 to 137.5. pilots being 122.5 to 125p with 1.8 n&s with pretty high popoff around 23 Ive tried this and always was pushing the lim on the main screw at 1/2 to 1/3 was lean lookng up top and too much fuel down low at cruise.

So this is what I came up with,went to 2.5 n&s with same 95 gram spring lowered pop off aprox 7 pounds to bring in the main faster,droped a size to 120 for the pilot and went up one size on the main to 140. I went out a little further with the pilot. "I know I cheated" and was able to get the main screw in to between 1/4 and 1/2 turn. This seemed to get the main jet online faster but at a more precise amount in the 1/3 range where it was muddy before.now its super clean.It would be interesting to try this with the 1.8 n&s and a slightly cut 65 gram spring. I know the high speed adj only comes in to play at 3/4 and above throttle,but with these full specs it seems change the mid range smoothness a good bit somehow.

 

[Big Kahuna]

I think reversing the carbs is effected more on runabouts that have some much side loading in turns vs standups that lean over in turns.

 

[superjetbrad]

i love mine no probs my set up is dual 48mm full spec main 135 @1/2 low 122.5 @1.0 n/seat 1.8 spring 80 pop off 23.5 with a jet in return line #60 on a 62t yam

 

[masterblaster]

^ thats the same jetting he gives 99% of guys out there,I just dont see how that same jetting guys run on a 701 is gonna be fine for say a 850 cc stroker big bore. and 23.5 popoff is what he recs everyone also,seeing a half pound on a guage right before it pops is kinda hard

big kahuna,Thats what I thought also,but chuckie made a big deal about it at tona on a 771 he built for one of our guys that wasnt running right,We had the 46 mil carbs on the ski pumps facing motor cause it was easyer to get the throttle bracket to work. We did get it running right but some other changes were made,so dont know if that made much diff?

 

[superjetbrad]

i thought the same but i got my carbs from a built sxr and didnt change nothin and it runs great maybe iam one of the lucky ones

 

[Flash-FX]

What's your solution to not have that 1/3-1/4 "muddy spot"? An accelerator pump.

The accel pump would make matters worse and dump fuel it in that problem area. But if one were to epoxy up all of those transition holes and re-drill them as to let in the right amount of fuel (not too small to create a lean seizure), that pump would probably eliminate any hesitation.

i love mine no probs my set up is dual 48mm full spec main 135 @1/2 low 122.5 @1.0 n/seat 1.8 spring 80 pop off 23.5 with a jet in return line #60 on a 62t yam

Some guys have all the luck.

MB, that regulator looking thing is a fire extinguisher.

 

[2XLR8]

^ thats the same jetting he gives 99% of guys out there,I just dont see how that same jetting guys run on a 701 is gonna be fine for say a 850 cc stroker big bore. and 23.5 popoff is what he recs everyone also,seeing a half pound on a guage right before it pops is kinda hard

I don't get it, If Ed designed the carbs I am sure he knows how to have them jetted. To think that a customer or someone in a forum is going to give better advise is hard to believe. How many real good running boats have been tuned to their full potential based on information received in forums?

 

[masterblaster]

2xl...very true,and my knowledge is nill in comparison,I tried his jetting and I found the same thing a flash did,a big muddy spot at 1/3 when the high jet comes in at cruise speeds. truthfully I dont think these carbs were setup or any r&d testing for cruising and surf riding.They were made to come out of the hole hard and get max rpm in racing.they do this very well. I doubt many rec riders were buying $1200 carbs when these 48s were made. We have a LONG cruise to our surf ride spot,so id like to enjoy getting there and not waste a ton of fuel doing it.

 

[Matt_E]

For what it's worth, I ran the older 48 Full Spectrum both as a dual setup and as a single on two different motors. There was no muddy spot.
Jetting per Ed's recommendation.

 

[Flash-FX]

How many real good running boats have been tuned to their full potential based on information received in forums?

Probably less than 5%.

2xl...very true,and my knowledge is nill in comparison,I tried his jetting and I found the same thing a flash did,a big muddy spot at 1/3 when the high jet comes in at cruise speeds. truthfully I dont think these carbs were setup or any r&d testing for cruising and surf riding.They were made to come out of the hole hard and get max rpm in racing.they do this very well. I doubt many rec riders were buying $1200 carbs when these 48s were made. We have a LONG cruise to our surf ride spot,so id like to enjoy getting there and not waste a ton of fuel doing it.

Let's not forget about loading up the plugs by the time you get there (the surf). It's a catch 22. If you jet small to run close to correct in the 1/3 area, you'll have to run the L/S screw out to beat the hesitation, and we know what that does. On the other side, run a bigger pilot jet and set the idle right, by the time you get to the 1/3 point, it's too rich again. :swordfight:

Bottom line....I've got a real nice array of jets and springs, all organized neatly in these cool pill containers......

 

[2XLR8]

I see most people buy 48 and 49 mm. What about getting some 44 mm Full specs for you cruisers out there. They should still hit hard for freestyle type of riding even with a stroker. Maybe selling the 48's and getting Ed to make some 44's for you just might be the ticket.

 

[Foximus]

Ed makes a big deal out of not having the main screw open more than a half turn,better metering circuit.
.

Ive never heard anyone else say that, but thats been more or less my thinking and goal for the last few months.... Interesting to hear a tuner recommend it too....



I'm really surprised though that ed recommends such a small n/s.... When I talk to other builders they dont... Art at jetworks says to stick with a 2.0, and Tim Judge even tells me to run a 2.3....



As for the 4 metering holes, its funny you bring that up because recently talking to Art about getting some blackjacks done, he told me he never really liked the idea of the 4th transition circuit, but we didn't go into any further detail than that, other than him saying something as to the point of "trying to fix a problem with another problem...." or something to that sort....

 

[kevbo]

I see most people buy 48 and 49 mm. What about getting some 44 mm Full specs for you cruisers out there. They should still hit hard for freestyle type of riding even with a stroker. Maybe selling the 48's and getting Ed to make some 44's for you just might be the ticket.

Im still looking for what is wrong with a standard sbn 44 and 46. What exactly are we getting from the carb modifiers besides something to talk about?