Fitech carb full throttle issues on 351 Windsor
Hello, I have a fitech 30003 and fuel pump 40003 set up on my freshly rebuilt 351 Windsor motor inside of a 20.5’ ski boat, so when I first installed it, It started great but I had to upgrade some fuel lines inside the tank so the carburetor wouldn’t be starved, I’ve taken it out on the water and I’ve been able to get it to go about 30 mph but it would bog down a lot and sound like it was hesitating to stay at that rpm, I have a brand new distributor on it that used to have points in it but I changed it to electronic ignition with the Pentronix 1281 ignitor and along with that I installed a Pentronix flame thrower 40011, I had the points in the distributor but I didn’t want to have to deal with dwell angle. I set the gap with the plastic gap took they send in the box. After I took it out on the water I was trying to figure out the issue and i started by setting my IAC steps between 3-10 but I didn’t quiet understand the instructions on how to do that so I ended up turning the screw in the back of the carburetor and it seemed to worsen my problem cause the next time I could only get it to go 15mph on the water before it started bogging down so I called Fitech to asked if they knew the stock setting for that screw in the back and they told me turn the screw till it touched and then back it out one full turn so I did and after that I set my idle rpm around 700 and set the timing at around 14 at idle but I couldn’t get the IAC steps to stay between 3-10 , it would jump around from 0 to 7 and back to 0 and then maybe 4, so I left it there and tried accelerating it to about 4000 rpm but the most I could get to was about 3000 rpm before it would start to miss and seems to be bogging down, even tried rasing Accel pump by 20% and it wouldn’t let me reach my max rpm, I have log files at home that show how it was running that I can upload later
First issue. The Pertronix Flame Thrower sends a dirty signal. Must upgrade your distributor.
So would I the Pentronix D134600 distributor be a good option ? The current distributor I have on there right now is a Prestolite 7020S and it doesn’t have advance
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Are you running timing control?
I have an old ski boat with a 351. Great motor. No Fitech on it though. Surprised there is no advance on the Prestolite as there is on mine. I think you may mean there is no vacuum advance on the distributor but there is mechanical advance. I converted mine to a Pertronix points eliminator(probably the same one you have.) Don't know if there is any problems with those and the Fitech.
As far as IAC don't be a slave to the suggested numbers. Many of us adjust for what the motor seems to want. Usually between 10 and 30.
Your problem is most likely ignition and timing. Do you absolutely know your firing order? Unlike Chevy Ford messes with firing order. On top of that it is a marine motor so there could be some difference there. Get your model and serial number and check with the manufacturer. OMC could well have a different firing order than Pleasurecraft. Or if you are like me and have a reverse rotation motor that is a whole different ball game. Once you are sure on that and have it right get back to us.
The pertronix points eliminator modules send a dirty signal to the fitech. There have been some guys that were attempting to fix the issue. Haven't seen any updates lately.
Two ways to fix. Go to a two wire distributor and run timing control or replace distributors with a quality electronic version. I have used a "Summit ready to run" for both setups on a Ford. Simply lock the distributor out if running timing control.
Quote from Austin DeHaas on June 14, 2018, 11:16 pmAre you running timing control?
No I am not running timing control
The pertronix points eliminator modules send a dirty signal to the fitech. There have been some guys that were attempting to fix the issue. Haven't seen any updates lately.
Two ways to fix. Go to a two wire distributor and run timing control or replace distributors with a quality electronic version. I have used a "Summit ready to run" for both setups on a Ford. Simply lock the distributor out if running timing control
Well it looks like I’m going to have to upgrade my distributor, and run timing control, you got an model number on the distributor you went with ?
Would this distributor I attached work ?
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https://www.summitracing.com/oh/parts/sum-850072-1/overview/make/ford
I would go with this distributor. There is a MSD adjustable rotor available for phasing. Part #84211
Reach out to Josh Williams on Facebook Fitech Owners Group. He has experience with using a Ford Duraspark distributor, modified to work as a Magnetic pickup. Probably a lot cheaper, but I haven't done it.
On my Chevy's I do something similar. I use the small cap HEI distibutor from a TBI motor. These factory distributors don't usually require phasing and can be trouble free.