Winter Project - 1994 SNOB

This is how I kept myself busy this winter in Utah.

The boat is a 1994 Ski Nautique Open-Bow with 351W Ford Pro Boss engine -- factory EFI and ProTech Ignition. In October, the muffler blew out, and prior to the muffler problem, the EFI and ProTech Ignition were both failing intermittently. One thing led to another...

1) Retro-fit from throttle-body EFI back to QuickFuel M-600 carburetor.

2) Re-jet carburetor for Utah altitude. (Main & Secondaries)

3) Install new mechanical fuel pump (pull block knock-out plate).

4) Install all new fuel lines from fuel tank to water separator and from water separator to new mechanical fuel pump. New "hard" line from mechanical fuel pump to carburetor. Remove all old EFI pumps and lines.

5) Retro-fit from ProTech Ignition back to distributor. I went with the Davis Universal Ignition "HEI" marine unit. The first distributor had a slightly bent shaft. I discovered this after installation. Summit Racing is great to work with and they swapped-out the bad unit for a new one. Old ECM unit, coil packs and wiring was removed. Sensors not removed.

6) All new "Live Wires" plug wires from D.U.I. (I need to have 2 custom wires made up).

7) New Muffler and wet exhaust hoses.

8) Exhaust manifold and riser gaskets appeared to be leaking -- and I couldn't have that, so everything came off. Manifolds and risers were hot-tanked at a local machine shop. Everything was re-painted with high temperature paint. New gaskets, silicone and fasteners. Exhaust system was re-installed with anti-seize lubricant and torqued to spec. I used grade 8 fasteners on the risers.

9) All new water hoses - raw water hoses to water-pump and from water-pump to engine.

10) New strainer.

11) Timmy T flush valve installed. I mounted this over the transmission on the bracket that used to hold the ECM and coil packs.

12) New high-torque starter.

13) New starter switch / solenoid.

14) Fuel sending unit (in-tank) had failed, so I pulled the tank and replaced the sending unit. I also capped the return fuel line to the tank as the mechanical fuel pump doesn't require a return line like high-pressure EFI.

15) Voltmeter was a bit wonky and that was also replaced.

16) Shower hose was nasty and the shower-head was partially plugged. New hose and shower-head.

Cost was approximately $2,200 for parts.

The only things left to do is install the 2 new plug wires and time the engine...that assumes that the engine will start!

JQ

Today was March madness - as it was the maiden voyage following the "winter project".

I went to lake this morning - armed with my timing light and tool box. Since completing the "winter project" I had not yet had a chance to start the engine. I'll admit that I was more than a little nervous as I was about to see what the results would be after I had just ripped out the EFI and ECM units and retro-fitted back to distributor and carb.

I knew that the initial distributor position is always a little rough and timing could be off +/- 20 degrees. I cranked the engine with the spark plugs out to get fuel into the lines, pump and carb bowls. With the boat in the water (still on the trailer), I was finally ready to see if the retro-conversion would work smoothly.

To my astonishment and surprise, the engine fired right up after cranking for only 2 seconds. The idle was a little low, but I fed in a little throttle and held about 1,000 rpm's to let the engine warm-up. I set the engine idle to 650 rpm's and got the timing light out and got down to timing the engine. I was again astonished and surprised to find that my "rough" initial placement of the distributor was right at 9 degrees BTDC. Dang! Pure luck...no skill on that one! I tweaked the the idle setting to 10 degrees BTDC then I ran the rpm's up to 3,000 and checked the timing curve. Very nice. Top end finished at 30 degrees BTDC.

The QuickFuel carb runs great out-of-the-box. All I did was re-jet for altitude. (The picture below shows the Holley 4160 before I pulled it off and installed the QF).

Overall, I'm quite happy with how everything turned out (yes, and pleasantly surprised and even a little shocked). I only found one little problem that was coming from a leaking hose connection (clamp was too loose).

I'm just glad that nobody was around the boat launch area to see me doing the "happy dance" and fist-pumping when the boat first fired-up.

:-]

JQ

Looks good! I also have a 94 SNOB with the protec ignition. I was wondering what symptoms you were having when you still had the EFI installed that made you want to switch to a carb? I've been struggling with mine and have been thinking about swapping back to a carb and distributer.

Hollywood wrote: Every time I see Jonny Quest from Utah posting I think of Point Break.

Vaya con dios, Brah!

1994nautique wrote: I was wondering what symptoms you were having when you still had the EFI installed that made you want to switch to a carb? I've been struggling with mine and have been thinking about swapping back to a carb and distributer.

Fuel Injection - I suspected that the fuel injection was going. I was getting dark gray exhaust while idling around. I could see that the EFI cluster did not have a uniform spray pattern. Upon closer inspection, I could see that one injector was spitting or dribbling. I took the throttle body apart and had a local injector shop run a diagnostic check on the injectors. One injector was completely "fried" but the other 3 were tweaked and given a clean bill-of-health. I called PCM and Holley looking for parts. The injectors I needed haven't been in production for over 10 years. Holley said that they hadn't carried them in stock for 7-8 years. Only 2 choices: 1) convert to a current TBI or Multi-Port injection; or 2) convert back to carburetor. I chose to go with the carburetor option because my Pro-Tech system was also starting to fail. EFI needs some kind of engine management system, so the retro-fit back to carburetor also meant going back to distributor. Package deal for me.

Pro-Tech ignition & ECM - This was a head-scratcher. Normally the engine would always fire right up, whether hot, cold, just of of storage, etc. Never a problem. Then suddenly after sitting for a couple of hours, the engine would not start. Not even a sputter. It seemed like there was no spark. This happened 6 or 7 times last year. If I would wait 10 minutes or so, it would mysteriously fire right up as if there was never a problem. After checking around (much on this web-site) I determined that my Pro-Tech engine management system "ticking time-bomb" was about to explode. I called www.skidim.com and PCM. Both said that my symptoms were typical of the Pro-Tech system that was dying.

Now that everything is back together, I'm VERY PLEASED with the engine's performance. I did not realize how poor the engine was running just before I started my little project. The injector problem had robbed much of my hole-shot, but top end seemed OK. Now I've got amazing hole-shot and top end is better at 4,000 of elevation than I was getting at sea level.

I would definitely recommend the Davis Unified Ignition H.E.I. distributor. It is a sweet unit. No need to worry about external coil or ballast resistor. Also, I would recommend the Quick Fuel carburetor. Originally I went with the standard Holley 4160 marine version that was OEM from Correct Craft/PCM. Not long after, I pulled the Holley 4160 and installed the Quick Fuel M-600 marine carb.

JQ

First Real Test...

Last Saturday, I took the SNOB out for the maiden ski voyage after completing the Winter Project. I had previously done two on-lake test runs to tweak the carburetor and timing. The real test I knew would come pulling a good skier. On Saturday, I had 4 people in the boat: 2 skiers and 2 boarders.

Dang! The engine performance far exceeded my expectations. Throttle response was outstanding and power/torque curve felt like a new boat. It makes me realize how poorly the engine was running at the end of last season. Hole shot was STRONG. 0 to 34 mph felt faster than I can remember.

I ran the boat at 4,400 feet of elevation. The prop was a new Acme 654. I was able to squeeze out 4,800 RPMs W-O-T with GPS speed showing 43-44 mph. Carb jets were dropped by 2 sizes because of altitude.

Nice to have the project finished -- and with such great results. I appreciate all the advice I've received from the CCF members. Just about everything I did had CCF fingerprints all over it.

JQ

Johnny Quest and 1994 Nautique...

I've heard and read here and other places that the entire fuel and ignition systems on our Mid-90's PCMs are not only tied together, but how parts are no longer available. I've been keeping my eyes out for aftermarket TBI systems, and ignition systems to retro-fit onto the 351W that has very low hours, but mine is still a 20-year old boat. I pray every time I go to turn the key. While she runs well now, I know at any time, I could be dead in the water.

Sure, MPFI is the best option, but I have to remind myself again, she's a '96, and I don't feel like dumping $2500 into a new air-fuel delivery system. And I know others have gone a more simple route, but going back to a carburetor, but I just can't stand carbs.

So far, when I look at Summit Racing, I have seen some TBI options for around $1900, and that's a lot of coin. I've just recently seen a different source, with a TBI system based on the mid-90's GM trucks, and they are advertising about $1K for their kit.

Has anyone had this condition and gone for an aftermarket TBI system? If so, how did it go, where did you source your parts?

Thanks,
PE

SNobsessed wrote: The problem with automotive FI is they are closed loop & need o2 sensor, which is hard to integrate into a wet exhaust system.

.Unfortunately, yes, the wet exhaust systems don't allow for the downstream O2, and drilling, tapping and using a location before water is introduced is too close.

Also yes, most current systems are closed-loop, but you can get them in an open loop configuration. Even some of the open loop ones can be tune-able, the ECU just doesn't use feedback (from the O2 sensor) to constantly tune itself.

I was curious if anyone had selected one of the open-loop options, and installed it.

PE

I'm finishing up the protec to carb conversion and was wondering if you had a part number for the hard fuel line from the pump to the carb?
Thanks
1994

I like the flexible line from skidim. A few more dollar$ but a good system.

Or, you can go to a local hose/hydraulic shop and they can build a custom unit with braided stainless steel.

JQ