91 SunSport runs rough after a couple of hours skiing, need some help

[BryanL]

I'm new to the Supra forum, but from what I have read already, I can use some of your assistance.
I have a 91 SunSport. Bought it new and have babied it from day one. The engine has 1340 hours and I have done some work on it over the years. At the end of last season I had the PCM Protect system replaced with distributor, coil, new wires, etc, by an experienced shop that works on lots of inboards. First time out the engine ran rough, stumbled, sputtered at idle and stalled frequently. Took it back to the shop and they did a compression check, checked the timing, fuel pump, etc. Everything check out but the carb needed rebuilt. Had that done. Second time out ran good for about 30 minutes then started doing the same things again. This time the mechanic came out to the lake and ran it around with me and adjusted the carb while running it on one of their shop gas tanks. He suggested that I have the fuel pick up replaced, so we did that. He also thought that I might have some bad gas. Third time out under the load of a skier it ran great for about an hour then started to run rough, not as bad as before. Today we ran it for about two hours under the load of pulling skiers and it ran great until the end. From idle it stalled and then took a few cranks to get it started. Ran a little rough back to the dock. I noticed that it just didn't have the same "humph" as earlier in the day.

I know this is probably too much information, but I could use some help. Any ideas what the problem could be?

[DAFF]

I'm thinking water in the fuel system. Runs fine when all the water is on the bottom. As it starts to be tossed about the water is mixed with the fuel and enters the carb. A small amount of water in the fuel system will create the same isues as you are describing. As you fill and refill the fuel system the water becomes less and less prodominate. Add some fuel line conditioner..... See what happens!!

[joel210]

agree on the water in the fuel. Also you can install a inline water/fuel separator. they are pretty cheap, they have an oil filter like canister that can be changed out.

[BryanL]

Thanks for the responses! I'll give both your suggestions a shot. Our summers here in Ohio are too short for these types of problems.

[Rusty]

Thanks for the responses! I'll give both your suggestions a shot. Our summers here in Ohio are too short for these types of problems.

I learned from this post. That is precisely what happened to mine. Didn't replace "fuel pick up"- what is that? Will my 87 salt are have one of those?

[BryanL]

I'm no expert, but from what I'm told at the end of your fuel hose in your gas tank is a fuel pick up. Some have a filter system on the end as well. The pick up can crack and this lets air in the system. From what my shop tells me over time these can clog or foul. The replacement part is like $20.00. I'm sure someone else on the forum can provide you with a better explanation.

[BryanL]

Since my last post I've added the fuel treatment and inspected my in line fuel filters. I've added about 15 gallons of gas to the tank. I was out yesterday and within about an hour and half it started to act up like before. I called Vince at SkiDim and shared with him my circumstances. He ask if the new coil that was installed last year was hot. It was. He seems to think that if the coil heats up more than it should, this could be part of my problem. The shop that did the conversion assures me that it was done correctly and said that coils will get hot. Any thoughts?

Has anyone had any experience with this type of issue? I mentioned in my earlier post that I had the Protec System removed at the end of last year and the PCM conversion kit to a standard ignition installed. Any suggestions would be welcome.

[wotan2525]

This still sounds like a fuel issue to me. There may be a fuel pick-up in the tank, but I have no idea how you would ever change it. The only access would be through the sender hole which is only about 3" wide?

Did you install the fuel-water seperator??

[BryanL]

I had the fuel pick up changed last week and i already have a fuel-water separator installed. Any thoughts on the hot coil?