1995 Pro boss / Pro tec

Well.... realized some bad news today....

I knew there was fuel coming from all 4 injectors.... but I didn't realize that at idle they're supposed to be "spraying" as opposed to "dribbling." I was under the assumption at first that my rich idle was the FI trying to get the engine warmed up .... but nope it's the injectors. All of them are dribbling. Unless they can be cleaned I think I'm hooped.

So I think I'm going to have to do the carb retrofit. I'm disappointed... but at the same time it will be nice to get this sorted over the winter. It appears as though everyone out there who has done the skidim carb retrofit has been very happy with it.

While doing the carb retrofit.... I'll probably do the DUI as well. So here's the thing... the Protec ignition system seems to be working flawlessly on the boat currently. It ran beautifully up to 44 mph @ 4800 rpm. Is the used protec setup worth anything? Anyone out there want a low hour spare protec system when I pull it off?

Ive read through a few threads already on the carb / dui conversion and it seems pretty straightforward. I've done a distributor swap on the 86 Nautique.

Does anyone have any recommendations/thoughts?

I wonder if they can be cleaned like mpi injectors by an injector service ?

MrMcD wrote: A simple trick to clean injectors is to put a quart of ATF fluid in the gas tank and go out and run it. I have seen it work many times to free up sticky injectors. It will not hurt anything and for about $4 it is worth a try. Gives you another reason to take the boat out for a long spin.   My 95 starts each season with a quart in the tank.

Just to keep things rolling...Synthetic ATF? Dino? Dexron III? Mercon?

JQ

Just to keep things rolling...Synthetic ATF? Dino? Dexron III? Mercon?   

JQ

Johnny, standard ATF not synthetic. I use the Dextron 3 because it is also used in my cars but I have read that the Ford ATF has more lubrication quality than Dextron.
It has been used for many years to clean injectors, started with truckers using it to clean Diesel Injectors many years ago.   It actually works very well to clean and lubricate.

I am pretty sure the EPA would not endorse it but it has proven to work so we use it.

Kind of like the 50/50 ATF and Acetone mix that works so well to loosen rusted nuts but is never sold over the counter at any store.

Probably 2-3 years back now I bought a rebuild kit for my throttle body. It had new blades, gaskets, o-rings, and regulator. I'll see if I can find the paper with the kit # tomorrow as I can't find the email where I ordered it. I believe it ended up being for a carb but worked perfect, I think I ordered direct from Holley.

Yes...the uber-scarce Holley 250R-123AA injectors. I had a shop clean and test mine. One came back “dead”. I looked for weeks in vain. I called Holley and they tried not to laugh when I asked them for replacement injectors...

Best of luck to you.

JQ

Jonny Quest wrote: Yes...the uber-scarce Holley 250R-123AA injectors. I had a shop clean and test mine. One came back “dead”. I looked for weeks in vain. I called Holley and they tried not to laugh when I asked them for replacement injectors... Best of luck to you. JQ

thanks! I need all the luck I can get :)

Hey guys, I had a really cool day hanging out with the injector guy.

He tested the injectors and here's what we found.

1. We did a leak test. Applied around 60 psi of pressure without any power and we found that they were sealed up perfectly. That was a win to start with.



2. We did an inductance test. All of them came out fine as in "not dead." That's also a relief. The one issue we have is there's an injector that's stuck closed. Which is weird that it ran to 44 mph at 4800 rpm. Anyway... the test shows that one injector is indeed stuck. Which means it may be no good.... OR.... best case scenario.... it becomes unstuck in the ultrasonic cleaner. Thats yet tbd.



If the ultrasonic cleaning fixes the stuck injector that's a huge win.
If not... I'm going to have three benched tested, ultrasonically cleaned injectors for sale for $100 USD each ;) ... hopefully pay for a good portion of a quick fuel m600 swap.

You guys should find out shortly.

Found it. Ordered them from Amazon. Holley 503-6 has the orings/gasket/regulator.

https://www.holley.com/products/fuel_systems/fuel_injection/throttle_bodies/throttle_body_components/parts/503-6

Quick question guys.... Do I need to run a mechanical fuel pump with a quick fuel carb setup?... or can I just use the low pressure pump that came with the pro boss Tbi injection. It's only 55 USD (almost 100 CAD after shipping and import fees). Small price to pay.... but you would think the low pressure pump would flow without issues.

Thoughts?

Fuel pump for carbureted systems.
I like fuel pressure between 5 and 7 psi. Per my fuel pressure/vacuum gauge, my Carter mechanical fuel pump produces 6 psi. I would counsel you to not use the low pressure fuel pump from the TBI set up. Go with a USCG approved mechanical or electric fuel pump designed to work with a carbureted system. Your old TBI system is also likely to have a return-to-tank fuel line. That return line needs to be securely capped off.

Spark arrestor.
My OEM spark arrestor that came with the ProTech TBI system did not fit on the QuickFuel carburetor. The reason for this is that the float adjustment hardware on the QF carbs does not allow the spark arrestor to sit flush on the carburetor mounting flange. I ended up going with a K&N spark arrestor/filter that has a raised flange so as to avoid the float adjustment hardware. Along with the K&N filter I purchased the K&N marine vent hose adapters for the breather hose and the mechanical fuel pump safety hose. If you need part numbers, send me a PM.

JQ

Any carb’d BBC from ‘91 forward and any SBC from 96 on has a good chance of needing an electric pump. Fords (carb’d) all had mechanical AFAIK.

Well it looks like I've worked out a deal for an entire Pro Boss TBI fuel system from low pressure pump to injectors, pro tec ignition system from trigger through coils, and ECU from the famous Boat Dr. I'll keep you posted how this works out.

Well that fell through. Back to square 1