Safe/Limp Mode 2000 Ford 351

[sgriff144]

First I apologize for starting a new post on this because I知 sure there are already posts regarding this topic on the forum. However, I知 at work and having problems searching on my mobile device. 2000 Sport Nautique has been running great this year. On Saturday, the boat pulled the first skier. I shut the boat off between skiers. Started for the second skier. Accelerated to pull the slalom skier up and started cutting out like a rev limiter. The boat now idles fine, accelerates fine until 3000-3200 rpm. The engine then cuts out until the RPMs drop below 3000, then repeats in a pulsating fashion. Check engine light comes on about 8-10 sec after the boat starts. Oil pressure, temp, and volts all within range. I bought a scanner on Amazon ( https://www.amazon.com/INNOVA-3145-F.../dp/B000EW0KHW ) for the EEC on the engine. However, I wasn稚 able to pull any codes when using this yesterday. Was wondering if people have used this scanner before or perhaps I need something different. The scanner advertises that it only covers up to 1995 car models, but this was the only reasonable priced one that I could find. Called numerous marinas in the area and none have this type of scanner. The closest Nautique dealer told me they aren稚 taking new customers at this time. I spoke to the guy at a former Nautique dealer that is 4hrs away in my hometown in central PA. He is extremely knowledgeable regarding the GT40 engines and has the needed scanners to diagnose and fix the issue. I will call the former Nautique dealer north of Pittsburgh tomorrow when their head mechanic is back. Any input would be greatly appreciated. Thanks!

[NautiqueJeff]

Very simple. Only two things can cause the boat to go into limp mode. One is an overheat condition, and one is a low oil pressure condition. If you really are experiencing either of those conditions, you need to figure out why. Sometimes the switches that control the limp mode fail though, and activate limp mode even though there is no real issue.

My bet is that the oil pressure switch has failed. You can disconnect the wire from that switch, and that should allow you to run the boat normally until you can get a new switch. It may also be the water temperature switch, and same deal with that, just disconnect the wire until you can get a new one and the boat will run fine.

Here's the oil pressure switch:
https://www.nautiqueparts.com/produc...nd-gm-to-2006/

Here's the water temperature switch:
https://www.nautiqueparts.com/produc...-mpi-r020014a/

We're talking about the SLOW system here. See diagram below.

[sgriff144]

You are the man! What else is there to say? Ended up being the oil pressure switch. For reference the temp switch is close to the top of the engine behind the water impeller. The oil pressure switch is on the stem that extends out above the oil filter. I have pictures for reference but need to remember how to use the second party page. Thanks Jeff!

[NautiqueJeff]

That's great! Glad that got you up and running!