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I`ve tried it all, the best fuel curve I got was block off all power valves and tune with jets.
Wanna lean out primary take jet out. but at the end of the day without a O2 reading he`s pissing in the wind. |
edited my post from 7/26
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Originally Posted by ICDEDPPL
(Post 4798920)
If you`re rich why would you add an unmetered fuel fill to your carbs?
Whomever had no power valves in there had it right. Powervalves belong in cars not boats |
i love like ...love to add o2 sensors,,,but it would be a big job,,,,and sensors would be in wet exhaust extensions,,,heard suggestion put in 90 degree adapter would solve wet problem...maybe..
i think i am going to start dropping jet size..go run boat mid range,,,,then pull a few plugs.. thanks for all advice....boats runs...just seems to fat... plugs are always black... thats some good fuel mileage thisisliving..........what rpm u at running 60...4500??? |
Originally Posted by ThisIsLivin
(Post 4799195)
I have a Pro Systems 1000CFM 4150 and I have power valves in primary and secondary, although I have restrictors in both. Carb runs great and I get really good fuel economy. Power Valves aren't always bad, if done right. I get 2.5mpg at 60mph all day long.
did u just put on your motors??? i am guessing you had to fine carbs somewhat??? thanks,,,,,,for advice... |
Originally Posted by flashgordon
(Post 4799261)
hello...thiisliving,,,,,,
did u just put on your motors??? i am guessing you had to fine carbs somewhat??? thanks,,,,,,for advice... |
Originally Posted by ThisIsLivin
(Post 4799296)
The problem with most carbs out of the box is they are designed for cars that have a multi gear transmission and can rev much quicker than in boats. In addition boats are under constant load. I spent years tuning my carb to get it just right and the proper ignition timing and curve are part of that. I have a big cam and in gear at idle I have 2.5" of vacuum. I had to change power valves, jets, accelerator pumps and squirters to get it to run exactly as I wanted. With a big cam and prop it takes longer to get on plane and build rpm's so I needed to extend the accelerator shot and timing to get me to the point I had some air flow to pull fuel. I ended up going to a 50cc on the primary with a .028 squirter on both primary and secondary. I had to use 2.5" power valve and as I stated earlier I have them on both primary and secondary. I bought an Otoscope to help read the plugs. I started the jets on the rich side and kept dropping them down based on the plug reads. Because I have almost no vacuum at idle it was hard to get the initial timing right. I tried special bushings in my MSD distributor to reduce the total advance so I had more initial timing. Then I ran the distributor locked which helped. I finally switched to a Daytona Sensors system that allowed me to create a custom timing curve with added idle control which made a huge difference. Now even without a choke she starts right up and I only need about 30 seconds of warm up and she's good to go. Once it's been started for the day I just give the key a quick hit and it's running. I know EFI can give you better cylinder to cylinder fuel balance. But when I pull my plugs, they are all identical even looking at them through my 10x Otoscope. I think some of that is due to the improved signal I get when I added a 4 hole tapered spacer. That also made a noticeable difference in performance. With motors as in life, everything matters and effects everything else.
wow........alot of info...but i like it... so do u run the daytona sensor system with your msd distributor???? so u replaced the msd box with the daytona system?? what motor and how big is cam?? thanks for info........ |
Originally Posted by ThisIsLivin
(Post 4799296)
The problem with most carbs out of the box is they are designed for cars that have a multi gear transmission and can rev much quicker than in boats. In addition boats are under constant load. I spent years tuning my carb to get it just right and the proper ignition timing and curve are part of that. I have a big cam and in gear at idle I have 2.5" of vacuum. I had to change power valves, jets, accelerator pumps and squirters to get it to run exactly as I wanted. With a big cam and prop it takes longer to get on plane and build rpm's so I needed to extend the accelerator shot and timing to get me to the point I had some air flow to pull fuel. I ended up going to a 50cc on the primary with a .028 squirter on both primary and secondary. I had to use 2.5" power valve and as I stated earlier I have them on both primary and secondary. I bought an Otoscope to help read the plugs. I started the jets on the rich side and kept dropping them down based on the plug reads. Because I have almost no vacuum at idle it was hard to get the initial timing right. I tried special bushings in my MSD distributor to reduce the total advance so I had more initial timing. Then I ran the distributor locked which helped. I finally switched to a Daytona Sensors system that allowed me to create a custom timing curve with added idle control which made a huge difference. Now even without a choke she starts right up and I only need about 30 seconds of warm up and she's good to go. Once it's been started for the day I just give the key a quick hit and it's running. I know EFI can give you better cylinder to cylinder fuel balance. But when I pull my plugs, they are all identical even looking at them through my 10x Otoscope. I think some of that is due to the improved signal I get when I added a 4 hole tapered spacer. That also made a noticeable difference in performance. With motors as in life, everything matters and effects everything else.
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Originally Posted by fbc25el
(Post 4799455)
He has a 4150 . That is a 2 circuit carb. What you have is 3 circuit. The intermedent circuit feeds too much fuel at part throttle. You should convert it to 2 circuits.
not sure if it was you or someone,,,but it was suggestted to make it a two circuit.... not sure how hard it would be... but i think a site or two was posted on this.. i did look at one of these sites...wow.. stuff they were talking about changing,,,i didnt even know what it was,,, was over my head.. just did a google,,found a thread on here from 2010...also don terrils speed talk... thanks info..... sounds like i should gt new carbs...any suggestions??? |
It may be cheaper to send them off to a carb shop. The main parts you will need is 2 circuit metering blocks.
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