View Full Version : I need closure

07-15-2010, 10:18 PM
and help
Currently I am having some fuel delivery system issues and am awaiting a water separator filter and a fuel filter from SKIDIM.
While doing endless searches on here I have noticed one thing staring me right in the face. When someone with similar symptoms starts a thread looking for answers, the answer is given several times throughout the thread by several people way smarter than me, but the solution for each problem is never ever given by the person that started the thread. Meaning that the people with problems are the only ones who know what worked for them not passing it on to the rest of us.

Here is my problem:
When pulling a skier or just cruising above 32 MPH for more than 30-45 seconds the boat cuts out and its almost like the throttle is pulled back to neutral. It has gotten progressively worse as of late, and has even died a couple of times if the throttle isn't played with accordingly. it always starts right back up and again runs fine below 3200rpms or so. I have it narrowed down to someplace behind the drivers seat, and suspect it is
1. bad fuel pump not keeping up with increased fuel demands
2. bad gas that has plugged up the water separator filter
3. clogged tank pickup/ check valve
4. something over my head in the carbereutor

Thanks to all in advance, and I promise I will complete this thread by giving the solution or solutions when it is found and solved.

So I guess what I am asking for is anyone that has had similar problems or exact problems chime in and help a guy out.

07-16-2010, 12:39 AM
Year? Carb or FI? Which carb if carbed. Only happens when pulling a skier? Does it happen at wot? What have you done so far besides order parts? I have been working on boats over forty years. Seen lots of different problems and learned how to isolate problems. The more information you post the easier it is to help. There are so wise people that frequent this site with MC specific information.

07-16-2010, 03:18 PM
SORRY. 1988 190 with 351 4160 carb. It happens at WOT as well as with a skier. So far I have changed plug wires checked plugs (all appear to be good) changed cap and rotor this season. That is pretty much it.

07-16-2010, 03:41 PM
Replace the water separater, and check quality of the fuel in the tank. I doubt it is the pick up in the tank that would be clogged. You also have a manual fuel pump. It may have a bad diaphram in it or the spring is worn out.

07-16-2010, 04:01 PM
If your water separator was in the condition mine was when I purchased the boat, plan to remove it and give it a really good cleaning. There are steel parts in it that rust when the water builds up and make a big mess plus clog the filter fast. Don't forget to replace the second filter that is in the fuel pump itself, in my case both were filthy from all the rust particles. Finally, take a look at the screen that is at the fuel inlet of the carb.

If the problem persists after all that, it might be worth putting a fuel pressure gauge inline for diagnostics.

If you suspect a restricted fuel line, you can also bypass all of the downstream fuel lines by running a temporary line directly from the pump to a fuel can and take a couple of runs.

07-16-2010, 06:10 PM
I am having similar problems with my 1997 ProStar 190. I have throttle body fuel injectors. We were out sking and lost power at high RPM's (above 2500). I replaced the fuel filter, just because it was the cheapest and easiest on my list of possible problems. Didn't help. Now I can barely get above an idle. The recommendations I am getting from these threads is to clean my water separator. Any other thoughts?

07-16-2010, 08:19 PM
how hard is it to ckeck the fuel perssure after the pump. Metal line makes it difficult doesn't it? Thanks to all so far.

07-16-2010, 10:02 PM
I would say it is a fuel issue. Engine is starving. Had a snow blower that did the same thing. Ended up being crap in the carb float seat restricting fuel into the carb. Replace or clean all the filters and water separator then move into the pump, carb or injectors. Fuel pressure gage is a good idea.

Hey the way I look at it is when you finally figure it out you will have learned a little more about your boat and the next time trouble springs up.

The previous owner on my boat removed the water separator. I have it. Don't know if I should put it back on. Where does it go?

07-16-2010, 10:06 PM
I had a similar problem with my 87 190, the carb needed rebuilt. I would think around 32 is when the four barrel starts to open and the problem may lay there.

07-16-2010, 10:20 PM
I wonder if you went in the wrong direction first changing plugs, cap and rotor. Never hurts to tune up a boat but that might not have been your problem. Remember you are working with gas. I can not stress enough that anytime you work with or around the fuel system--fire and explosion are a real threat. Start at the fuel. Pull a sample down stream from the fuel tank through the fuel system. Replace the fuel/water filter. Look at it the old one. Make sure your carb doesn't have stone filters or screens at the bowls. I don't know if that Holley does or not. You can hook a gas line past the fuel pump and turn the engine over and look at the stroke volume but that is a subjective non-scientific measurement. Several things could fail with mechanical fuels pumps but in my past either they pumped gas or not while leaking gas or not leaking gas. Not knowing the difference between auto and marine--in the past if the diaphragm was bad they leaked gas through the weep hole while they still pumped gas everywhere. Base gasket good? Next on the list would be the carb. It is a Holley and they sometimes need a professional to rebuild. If I was getting good fuel to that carb and I suspect you are then I would really be looking at your carb. I suspect your secondaries or secondary needle valve and float. Just a shade tree educated guess. If that boat runs good below 3200 rpm and around 32 mph but runs like crap past that sound like fuel starvation.

07-17-2010, 12:24 PM
My in-laws had the same problem. Turned out to be the check valve located at the top of the tank. It was clogged with fibers/debris that must have gathered over the last 25 years. Before finding that I had changed the water separator and cleaned the screen filter located where the fuel line enters the carb. Good Luck!!!

07-17-2010, 01:12 PM
There are MANY things that can cause the symptoms you have. If you thinks it's a fuel problem, as already mentioned I would first check fuel pressure rather than guessing. If the pressure checks good, then you can look at the carb. My boat is TBI and there was no fitting to check the fuel pressure. I had to buy an adapter to put in place of my in line filter in order to attach a fuel pressure gauge.

07-17-2010, 07:26 PM
well since I'm waiting for the filters, I decided to try and pull off the check valve to see if its plugged or stuck. I can't seem to get it almost like its welded together. I don't want to turn too hard for fear of breaking it. Any ideas? WD-40 or the like. Just unsure seems to be aluminum.
Also, for what it's worth, the last time the boat sputtered and acted up, I took off the flame arrestor and looked into the carb and did not see any gas so much as drip into the throat from the venturis. Don't think it should be like this, but again just something I forgot to add

thanks again all.

07-17-2010, 10:00 PM
My boat acted like this when we bought it. Turned out to simply be a fuel filter that was likely WAY past due to be changed. In addition, I found some junk at the inlet of the fuel pump.

07-21-2010, 02:49 PM
thanks for everyone's input. turned out to be one of three things that I did all at once.
1.water separator filter
2. fuel pump filter
3. sea foam in gas on fill up.
thanks again to all

07-21-2010, 05:23 PM
thanks for everyone's input. turned out to be one of three things that I did all at once.
1.water separator filter
2. fuel pump filter
3. sea foam in gas on fill up.
thanks again to all

Glad you got it working! :D