Boat Hesitation

I am experiencing the same sort of problem with mine. I asked for help in a post a couple of weeks ago and really still do not know the answer. I have changed my fuel filter and cleaned the anti-siphon valve on the fuel tank. Still having the same problem. Just got off the phone with Discount Inboard Marine. I am going to replace the 2 relays for the fuel pumps. Fairly cheap repair about $12.00 a piece. I am working through it from the cheapeast parts to the most expensive. I will keep you posted on what I find.

Just to give you some insight on what I am experiencing it began happening to me it seemed while my boat was under a load. But now it seems more to happen after I run the boat a while shut it down for a hour or so and then get going again. It typically happens when I am trying to get the boat up on plane. I can put the boat in neutral and then start again and it works fine and does not happen again until I shut it down for a while.

The one thing that makes me think that the problem is somewhere between the fuel tank and the low pressure pump is something I experienced while changing the fuel filter. I changed the fuel filter and I followed the instructions which say cycle the key several times to fill up the fuel element canister. Once I thought I had the fuel element full I put the boat in the water and tried to start it. I would not start so I attempted to drain the fuel element to take a look thinking I messed something up and when removed the drain plug very little fuel came out. I placed the hose in a cup and cycled the key and the fuel poured into the cup. Therefore, based on that experience I feel the problem has to be somewhere between the tank and the low pressure fuel pump. I am going to change the relays and if that does not work I am going to change out the low pressure fuel pump.

I have a 1998 Pro Air Nautique with a PCM Apex engine. Hopefully the fuel filter will solve your problem but it sounds almost identical to what I am experiencing. I will get you posted on what I find.

Hope this helps.

On my boat I followed the instructions word for word on installing the new filter element and it does not discuss filling the canister prior to installing. It says to reinstall canister and then cycle key several times to fill canister. However, on the top of the canister it has an air valve stem similar to a bicycle tire stem which I did use to bleed any trapped air. My boat runs great 99.9% of the time. But from time to time for whatever reason it hesitates for just a second and then it runs like a top. I think it is related to either the relays or a faulty low pressure fuel pump. I should know for sure in the next week or two.

My boat also had gas that was a year old with no stabilizer put in it.

I put injector cleaner in my old gas and it seemed to work good this past week-end.

did you clean the passage for the IAC when you replaced it. Might take off and clean the throtle plate and makesure there isn't a small vaccum leak, sometimes the butterfly plates can come loose on the shaft that rotates them.

I had mine boat checked and it was the fuel pump relays. The mechanic replaced them. I'll be back on the water today!

Guys I had this exact problem with my 96. It turned out to be the hose that ran from the high pressure pump to the rail system inside the fuel canister. It had a small half inch slit in it.

It was also causing it to slightly overheat. It was running around 180 to 200.

I'm tryin to go back in my mind to when I did this......everythings a bit fuzzy. I musta been drinkin a beer (or two) while I did it.

Ok lets break this down. Low volume fuel pump on the passenger side of the motor block down low. It flows fuel into the large canister also on the passenger side, it's about 5 inches round and roughly a foot long. Inside the canister is the high volume fuel pump and, I think, the filter your gonna change. Correct me if I'm wrong guys. This canister screws off. Righty tighty, lefty loosey. When all this drops down you'll see the fuel pump hanging by a couple of 1/4 inch fuel lines and a couple of wires. The wires have a disconnect and the hoses have clamps. If you don't wanna unclamp it, you may be able to see any damage just by moving the pump around. If these hoses are black, they need to be replaced. The ones Nautique used were clear. I could only find black ones to replace'em.

I found the problem after messin with it for close to a month two years ago. It was drivin me crazy. I finally ran a pressure test on the fuel system and it wasnt very low. But it was low enough.

Keep us posted man, I hope this helps.

Actually I have not yet solved the problem. I plan on changing out the 1/4" fuel line inside the high pressure fuel pump. It is a nagging problem but does not ruin my boating so I have just dealt with it. I plan on changing that line soon and when I do I will post the results.

The one thing have done is I plugged in a fuel pressure gauge to the tire valve on top of the Fuel Control Cell. My problem is almost predictable so I watched the pressure gauge on startup and it ran anywhere from 38 - 42 psi most of the time. When the boat began to hesitate I could see the fuel pressure drop down below 20 psi. I can put the throttle in neutral wait a couple of seconds and the fuel pressure returns and away I go. It is annoying but I can live with it for the time being.

I would appreciate you keeping me posted on what you find as well. I plan on doing the cheapest stuff first before I move to the more expensive repairs.

Trav, I sure hope you get it figured out. Keep us posted.

Where do you ski around Victoria?

I agree about the carb'd vs EFI point. NECC didnt think it was fuel pump related either. My symptom is similar to what I've read about an engine that goes into "limp mode". It starts up fine, sounds normal, you put it into gear and at around 25-27 MPH it begins to sputter. From there, you can throttle down to below 25 MPH and it runs fine, but you cant go back up over 27 MPH w/out the sputter. All's I do is shut the engine off, wait about 15 seconds, turn it back on, and its fine. This happens about once every two weeks. Its like I "reset" the ignition system and everything clears. NECC is talking about a new ignition kit at around $600-$700. The symptom is not occuring any more frequently, and to clear it up is easy. Therefore, I'm gonna pause on the repair for now. The odd thing is that it happens in such an irregular fashion. You'd think that this would happen every time you start up. If that was the case, it would really be a problem.

Just to be clear, DavidF's advice is for Traveller and his GT40 issues.

92NIQUE, limp mode will limit your RPM's to 2500, IIRC. If you try and go over 2500 while the motor is in limp mode, the boat will go into a high frequency stutter and stop accelerating. Our '92 did this many years ago, and I think a faulty knock sensor was to blame.

I would think testing each sensor that could activate limp mode to try and eliminate the ignition itself as the culprit would be cheaper than simply replacing the whole system. I suppose it could be hard to troubleshoot since it is an intermittant problem, though. Unfortunately I dont know enough about the Protec system to give you any more specific advice.

Just remember that you lose your engine protection system (limp mode) if you replace the Protec. Hopefully the 600-700 includes retrofitting the boat with a warning light/alarm like the older boats have. If they were simply replacing the ignition parts (coil and distributor) then it shouldnt cost that much. My DUI performance ignition system is probably the most expensive upgrade out there and it cost me less than $550 in parts. An experienced tech could do all the work in less than an hr.

Thanks for all the help you guys are providing it is great information and will be utilized. Just for the record the engine in my boat is actually an APEX engine not the GT40. Don't know if that makes any difference.

I did change out both of the relays with no change.

I don't have a lot of experience with the "limb mode" but I really don't believe that is what the problem is. Simply because if I try hard enough I get keep the boat running by goosing the throttle. It takes a few seconds to get the fuel pressure back and get going solid again but I can do it that way if I choose. It is just a lot easier to bring it down and then start again. My skiers don't always like it but they are getting more use to it.

My fuel pressure is dropping whenever it happens so it would be interesting to know if the "limb mode" actually drops the fuel pressure to control the RPM's.

One thing you guys mentioned that might help me is when I purchased the boat last September it did not have the oil pressure sending unit on it. The hole for the sending unit was plugged. The guy I bought the boat from gave it to me at the first of the summer and I installed it. However, he did not give me all the parts so the sending unit wire is connected but the low pressure wire is not. I never experienced this problem until I connected the sending unit wire. But, I did not run it very much over the winter either. Not sure if that has anything to do with it but it might be worth my while to disconnect the wire and see what happens.

If I had to make a bet on what it is I would say it is either the hoses on the high pressure fuel pump inside the FCC or the actual high pressure pump itself.

Please keep these comments coming it is all good information.

Thanks again for all your assistance.

After I left my last post I decided to call Vince at Discount Inboard Marine. The last time I talked to Vince he stated that he really could not give me any direction until I determined what the fuel pressure was doing.

Anyways, Vince stated that he really should boil down to 4 problems:

1) Some type of restriction in the fuel line or possibly in the tank.

2) Could be the fuel hose in the FCC that comes from the high pressure pump.

3) Low Pressure Fuel Pump Malfunctioning

4) High Pressure Fuel Pump Malfunctioning.

I asked him if there was any chance any of the sensors such as the TPS sensor, etc could be causing the problem and he said no. He said if you are losing fuel pressure it will come down to one of those four things.

I will keep you all posted.

Thanks for the assistance.

You are correct in this statement. I have the wire that goes to the sending unit hooked up. There is another wire that connects to the a low oil pressure sensor. That wire is not connected and from talking to them at DIM it is ok to run it without it hooked up so long as your oil pressure gauge is connected and working properly so you know you have good oil pressure.

When connected properly if the computer senses low oil pressure it will shut the boat down. I asked them at DIM about this wire and he said he should not effect anything if it is disconnected. Hopefully they know what they are talking about.

I have all the parts to put it together but it seems like the only time I ever think about putting it on is when I am about to put the boat in the water to go out. I plan on getting the low oil pressure sensor put on this winter but for now it runs ok without it.

From talking to Vince at DIM I asked him was there anything in the computer system or elsewhere that would tell the fuel system to drop the pressure and he said no. If that is correct then I have to assume my problem lies with one of those 4 remedies he gave me.

Only time will tell and I have to get enough time to work through these items he gave me to find the problem.

Thanks for the comments keep them coming. I have been working on inboard boats now for about 6 years and these message boards have helped me solve many a problems.