2001 Nautique 196 hunting and stalling.

New to the forum so would like to wish everyone best wishes from over in Ireland.

I hope I am posting this in the correct place because it may end up quite a long post so apologies in advance.

After many years of sports boat ownership I finally purchased a 2001 Nautique 196 last year. Boat was a bit of a project, new upholstery required, general tidying and had been inactive for a couple of years. I knew a little of the history of the boat and the issue I am having has probably existed for some time but now we are at the stage where the boat will not run for much more than 10 minutes.

Generally fires up first turn and runs smoothly, or at least to my uneducated ear. The problem begin after around ten minutes or when engine generates heat. I am not sure whether the issue relates to electrical, fuel or heat. Engine would pull fine in the water, would lift a skiier no problem but starts hunting and eventually stalls. Will sometimes start again but will get to the point where it is very difficult to start. Will generally start if left for a while.

I have found several references to problem similar to mine so I have done some things which would seem to cause the above problem. I have checked breather to fuel tank, condition of pipework to and from fuel tank, strainer on fuel pick up, added fresh petrol, checked strainer in LPFP, applied power directly to LPFP (seems ok but have not actually calculated rate of flow), changed FCC filter, checked pressure when boat is running at Schrader valve on FCC, not quite 40PSI but close. Fuel pressure does not drop noticeably when engine is hunting or eventually stalls. Pressure seems to increase slightly if I look at pressure gauge several minutes later.

I have changed relays and the housings that connect the relays as these had very poor looking connections. I have changed the spark plugs and leads. The 60A main breaker was stuck so I replaced that. The 12.5 and 15A breakers seem ok but that is just visual and a wiggle. I have checked several earth cables and all seem ok. I have replaced the coil and the alternator. I have replaced the battery and fitted new terminals.

I have not yet removed wiring and checked connections at the ECU. I have read several posts with similar symptoms to mine but, as I live in Ireland, access to even fairly basic parts is quite limited. I would really appreciate if someone could suggest what to try next and possibly point out anything obvious or simple I may have missed.

The original owner did have some issue with stalling but it is not as bad as I am experiencing. He would have used the boat for hours before any issue and the boat would have fired up a few minutes later and been fine again. There have been three distributor caps fitted over the years and the current one looks brand new so I did not replace that.

I did mention heat earlier in the post. I have fitted a new impeller but the constant running from a hose has probably done it no favours. The exhaust risers get quite hot, I have no idea how warm they should be but I do have an infra red probe to check. Water coming out exhaust is quite steamy. Oil change done and no signs of any moisture in oil.

I am currently waiting on a simple fault code reader coming across from America but will be a few days before I see that. I have no problems throwing some parts at this, it is now 17 years old and many components will be past their best. My main issue is waiting at each stage of the diagnosis for parts to arrive, get across to boat, get them fitted and test. Summer is wearing on and nothing I have done has had any effect.

I may have forgotten some things I have done/checked but this probably covers most of it.

Many thanks in advance for any help.

Best Wishes,
Neil.

I guess this is a gt40 engine? Running on gas?

macey wrote: Hello, thank you both for the prompt responses. It is running on gas as opposed to LPG. When you suggest spraying fuel directly when it starts hunting and wanting to stall do you suggest removing the flame arrestor and introducing the fuel there? Thanks, Neil.

Correct. Introducing petrol (gas or gasoline) into the intake manifold can help isolate the problem. If the engine will run with petrol squirted into the intake manifold, but won't run properly without the added petrol, then you have some valuable information.

I like to use a spray bottle with some type of atomizer rather than just a stream of raw fuel. Just use caution and a little common sense here. With the flame arrestor removed, a back-fire while holding a bottle of petrol nearby is not a good scenario.

JQ

Hi Macey,

I had a 97 SN with the GT 40 engine. It had a similar issue and it turned out to be a 1.5 inch clear plastic hose in the Fuel Control Cell (FCC). The hose develops a split that opens up as the engine heat builds, thus causing the problem. I recommend replacing the hose, Discount Inboard Marine should have these in stock and Vince can provide you with one. See www.skidim.com.

Good luck!

Hi Pete, have seen a few posts with reference to this part. Did take a quick look at this when changing the filter, it did look ok but I didn't bend it too much to find cracking. Would deterioration of this pipe be in keeping with my fault?

No worries, that hose issue plagued me for months. Three different dealers couldn't find the problem so I traded for a 2004 SN, very happy with it.