Thread:

Squirter Sizes

Originally Posted by Ahsumtoy

I have a 565ci 950hp chevy in a jetboat. It has two AED 1050's. The engine stumbles pretty bad when I transition from say 2500rpm to full throttle. The carbs have .035 squirters which I believe need to be larger. My question is how much larger? I've been told to go to .045's. What do you suggest?

One step at a time. Doccument the changes. May need some airbleed adjustments too. I'd call John at AED and see what he says. Really nice guy and very helpful.

Single biggest thing is "when?" Right at the hit?, just after, or a second or two after?, and how long is the stumble if it recovers on its own with out imput from your right foot? Its the difference between a squirter change and a cam change.

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Originally Posted by gn7

Single biggest thing is "when?" Right at the hit?, just after, or a second or two after?, and how long is the stumble if it recovers on its own with out imput from your right foot? Its the difference between a squirter change and a cam change.

Agree with this. We've run a similar engine combo and a pair of dominators should have enough squirt to leave from an idle with 35's. If the squirt adjustment is right it should leave cleanly.... With a single dom, we had to go up in squirt size to equal almost the same squirt nozzle area as with dual doms....
Squirts are available clear up to 50's or so. Maybe bigger, but that's as big as I've messed with. They're pretty cheap and easy to change. Might be worth trying some.

Just thought of something else. Are the carbs soft progressive or 1:1. By 2500 RPM, you may be almost through the primarys if it's a soft progressive and just have the secondary squirts left. Sleeper CP has messed with this stuff a bit I think.... hopefully he'll jump in here.

Originally Posted by David 519

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Just thought of something else. Are the carbs soft progressive or 1:1. By 2500 RPM, you may be almost through the primarys if it's a soft progressive and just have the secondary squirts left. Sleeper CP has messed with this stuff a bit I think.... hopefully he'll jump in here.

This is an excellent point. I believe the AED's are equipped with an adjustable external secondary linkage. Have you tried running it with 1:1 or the different rates of progression? It can make a big difference when the hit is after a part throttle opening. If it does not stumble from an idle, I would seriously look at the secondary setup. The secondary rate does virtually nothing for an off idle hammering, but plays a big part in a part throttle hit.

Originally Posted by Ahsumtoy

The carbs are progressive. Other than jetting on the dyno, and idle adjustment, they are how they came from AED. The boat never stumbled from low speed, but never hit it to full throttle from low speed either. When I hit it at approximately 2500rpm it would stumble right away and recover with no additional throttle action. Info from AED says the air bleeds are set at middle of the road and may need adjusting. They also say if the engine hesitates at full throttle transition the squirters may need to be changed to a larger size.

By the way, no problems with hesitation occurred on the dyno, but I suppose that it wouldn't on the dyno. This is only the second time the engine has been used, the first time I had issues with the floats and that problem is now gone. I only mention it because essentially this is the first time the engine has been used, other than on the dyno.

Yeah the dyno is a tough place to work out carb issues. Unless its an Eddy Current dyno, its almost impossible to duplicate the load pattern of the boat. In our case, and simple gear change or prop change can change the tip in requirements. And shooters are the hardest. Half the time I dyno a motor I disconnect the secondary shooters because its easier on the throttle servo and seems to allow for more pulls, and I have never seen it stumble on the dyno.

Ahsumtoy, it sounds as simple as a larger shooter, and if possible, rotating the primary cam back to delay the shot if there is a screw hole to allow for it. One is free, the other requires you to buy some shooters.
You can also try changing the secondary linkage if it is the external adjustable type. Maybe try a slightly quicker opening rate so you get into the secondaries sooner, the primary throttle angle is less and you use up less of the shot before it sees the hit.

I know this may sound fundamaental and I don't mean to be insulting, but make sure the pri. pumps are adjusted for maximum travel. Throttle wide open, maybe .015-.020 before the lever bottoms out in the diaphragm. This way you'll get maximum travel out of the pump arm. If there's too much clearance, you're losing some pump stroke no matter where the cam is.
Having said that, the primaries should be transitioning into the main circuit by then and shouldn't need any more squirter. It sounds like a circuit transition which you'll need to adjust with airbleeds, I believe. IIRC, bigger air bleeds, the sooner the transition.

I agree Scott, the primary main system should be active, but it still possible to overwhelm a main system with a sudden drop in velocity when the blades snap open, and it could still need a pretty healthy shot. I would think that 4 pumps would be enough, but it depends on the manifold. Like I need to tell you that.

Maybe I am wrong, but I believe a smaller bleed, aka air leak/vacuum break will result in a quicker response time on the circuit.

Ashumtoy, like Scott said, it may seem like another stupid question again, but the fuel level plays a huge part in the mains ability to stay active at a velocity drop. Just one more little thing.

The fact that it stumbles right at the hit and recovers pretty quickly, gut says it will all work out with shooters maybe 2 maybe 3 sizes larger all around. I sure as hell wouldn't go to .45's
But I would try the simple, easy, free, double checks first.

Originally Posted by gn7

I agree Scott, the primary main system should be active, but it still possible to overwhelm a main system with a sudden drop in velocity when the blades snap open, and it could still need a pretty healthy shot. I would think that 4 pumps would be enough, but it depends on the manifold. Like I need to tell you that.

Maybe I am wrong, but I believe a smaller bleed, aka air leak/vacuum break will result in a quicker response time on the circuit.

Ashumtoy, like Scott said, it may seem like another stupid question again, but the fuel level plays a huge part in the mains ability to stay active at a velocity drop. Just one more little thing.

The fact that it stumbles right at the hit and recovers pretty quickly, gut says it will all work out with shooters maybe 2 maybe 3 sizes larger all around. I sure as hell wouldn't go to .45's
But I would try the simple, easy, free, double checks first.

I don't dissagree. I could have the airbleeds backwards...been a while. Do these carbs have PV's?

Originally Posted by steelcomp

I don't dissagree. I could have the airbleeds backwards...been a while.

And your getting old. Try some ginkgo biloba and try to get more sleep.

Originally Posted by Ahsumtoy

No PV's. The carbs have .035 squirters, Quick Fuel sells .040, .042, & .045.... Since I have a couple of sets of .035's I figured I'd just drill them out to ______?

Here's a picture of the linkage. Not sure what ratio this is? Do you still think I should change the ratio? And if so to what? I'll also check out the pump clearance and get back to you.

Here's some tuning info from Holley. Unfortunately I couldn't find anything on adjusting the linkage. I think you're going to have to just do the tirial and error method. HOle one looks furthest away from the center of the primary shaft and will give the fastest opening on that side...not sure what hole(s) it might corrrespond with on the secondary side.

Yeah, if you have the spare shooters, by all means drill them. Its not exactly like drilling a jet. I would never recommend that. But shooters are not that accurate. You'll need a pin drill set and a pin drill. You can start with about a .037 or there about.
But first let me see if I can find out which holes do what on the linkage. I use to know but its been awhile since I messed with it.
But getting back to what David and Steel both eluded to, if the secondaries are completely closed, you have to cover the secondaries till they come on line. Like Steel said, once the main is active, it takes less shot to cover for the velocity drop and change in the pressure differential. But if the secondaries are dead, the shot requirement becomes larger to cover till it comes on line. And its trying to do this while the air across the boosters has almost stalled due to the sudden decrease in velocity caused by the throttle opening suddenly becoming some 10 + times the size compared to primaries cracked open.
If you open all the barrels at the same time, and all the mains are active when you hammer it, and it doesn't hesitate, you know your only trying to cover for the secondaries being off line at the time. I would still fix it with a larger shooters in all 8 barrels because it will help with the distribution during a critical time. But it would tell you if its just a shot problem, and its free. You may be able to just leave it that way if it works. Its just that it can be a little bit of a hand full if the throttle gets real touchy. Its easier to control 4 throttle openings than it is 8.

Edit: Ok the higher the number, the sooner the secondaries open, til number 4 is pretty much 1 to 1. So right now your pretty progressive and your secondaries are most likely not active when your at 2500. Id try number 4 and see it things are better. Its free. Its simple. Its one of the things you paid good money for. Use it. You never know, you may leave it like that.

BTW, is that a water spots I see on the spring attachment on the linkage. Whats up with that? What a slacker.