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He is almost there . I'm wondering if he had the dreaded off idle fuel pressure creep
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The guage I got was an inexpensive mr gasket that I could screw in to the fuel rail. It was flickering a lot under load. I don't trust that guage I'm going to bring down a snap on one. Or maybe get a beter guage my last boat had auto Meter guages in line and they read rice and steady. This gauge flickered a lot maybe because cheap guage ?
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Originally Posted by SB
(Post 4184120)
8 psi is totally fine. Actually, 7-8 psi is perfect. You don't want to be higher though.
If the idle speed screw is opened too far you will have enacted the main fuel system and thus fuel will come out of the boosters. I'm assuming these are what the OP is calling the 'ring.' If there is too much fuel pressure or the float is set too high or the needle and seat is stuck, the fuel will come out of the vent tube. OP - don't take this wrong but your actions on the new carb (jetting/metering block changed over from old carb) and some of your terminolgy tells me that you don't know all that much and it may be time to look over the shoulder of someone who knows more. I learned without someone like that but it's not the faster nor cheapest way to do it. We can only help so much from here. Our hands can not go thru the computer screen - if you know what I mean. Ya I understand thanks. The fuel hasn't come out of the vent tube only the booster. That was in the old carb. I'm pulling my hair out and yes trying to get someone to come look at it with me. |
OP I gave myself the same advice in fact I learned that not a lot of modern mechanics really understand carbs. I took it to an old timer that has done carbs for 40 years and he reset everything to factory specs and I re installed it and the boat runs great. A skilled guy can likely tune it some more but its dam hard to find a guy that can tune a carb without O2 sensors and is willing to do it on the water.
Originally Posted by SB
(Post 4184120)
8 psi is totally fine. Actually, 7-8 psi is perfect. You don't want to be higher though.
If the idle speed screw is opened too far you will have enacted the main fuel system and thus fuel will come out of the boosters. I'm assuming these are what the OP is calling the 'ring.' If there is too much fuel pressure or the float is set too high or the needle and seat is stuck, the fuel will come out of the vent tube. OP - don't take this wrong but your actions on the new carb (jetting/metering block changed over from old carb) and some of your terminolgy tells me that you don't know all that much and it may be time to look over the shoulder of someone who knows more. I learned without someone like that but it's not the faster nor cheapest way to do it. We can only help so much from here. Our hands can not go thru the computer screen - if you know what I mean. |
You calling me old ? How dare you.
LMAOF. |
Here's the update. Hooked up fuel psi gauge and watched while the surge was occurring. It's holds 7 lbs of pressure steady. Swapped carbs and it still does it. It's not the carb. So must be ignition. Ign module? I have the setup with knock sensors I believe. If I keep the boat will probably go to DUI ignitions
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Any chance u can point a timing light while cruising and watch and see what the timing is doing during the surge? Swapping the module from the other engine might be a good idea
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Ya ill do that next. I think they are all the way in the back and hard to get to. Thanks for all the help ! Does the ignition module in this look like a thundebolt one? I cant see it think is by the black box back of motor left of the distributor if you looking front to back?
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Where's your base timing set at? If it's too high the knock sensor could be pulling timing out and that could be your RPM drop.
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You might consider swapping the knock sensors too, just for sh!ts and giggles. Do each component swap one at a time to rule them out. I guess that is one benefit of having twins - being able to swap an identical known good component. I have to give you credit for sticking with it. If this was me with my schedule, it would be drawn out over about six months. :p
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