Cuts out at speed

[Stevensc]

New to forum. Looking forward to making new friends! I just purchased a 1998 VRS 200. My issue is.... it runs great at low to medium speeds but when I get close to wide open the motor will suddenly cut out completely just for a second then take off again. No warning, no skipping, just shuts down and takes off again. Any suggestions are greatly appreciated. Thanks

[waterlogged882]

New to forum. Looking forward to making new friends! I just purchased a 1998 VRS 200. My issue is.... it runs great at low to medium speeds but when I get close to wide open the motor will suddenly cut out completely just for a second then take off again. No warning, no skipping, just shuts down and takes off again. Any suggestions are greatly appreciated. Thanks

I got nothing. Best on the fix. JimN (below this post) knows his stuff on engines.
.

[JimN]

New to forum. Looking forward to making new friends! I just purchased a 1998 VRS 200. My issue is.... it runs great at low to medium speeds but when I get close to wide open the motor will suddenly cut out completely just for a second then take off again. No warning, no skipping, just shuts down and takes off again. Any suggestions are greatly appreciated. Thanks

Always check fuel pressure if performance issues arise, especially if it happens at higher speed. Next, check all grounds- battery posts may look clean, but they may actually be dirty and if you use the zinc clamps on the battery cables, they need to be tightened- I have seen many boats where the owner complained about things not working but it turned out that they just slipped the clamps onto the posts and turned them "to make better contact". If possible, find a dealer that has a diagnostic computer- you don't know the boat's service history and it will give you a good baseline for the future. in fact, a marine survey wouldn't be a bad idea because it digs deeper into the engine and the rest of the drive system.

When you check the fuel pressure, the recommended test is done with KOEO (Key On, Engine Off), at idle, 2000 RPM and at WOT (Wide Open Throttle) and the gauge should have a purge valve to eliminate air in the line to the gauge- this valve is also used to take a fuel sample and I strongly advise collecting about a cup of fuel in a clean, clear bottle. Let it sit for about 5 minutes and see if any water settles out. If you see a layer of milky liquid at the bottom, it means Ethanol has mixed with water and it is probably a contributor to the problem. This needs to be removed- no additive will eliminate it. If you see anything else in the gas, get rid of it. If the gas smells strange, get rid of it. If it has a strange color, red or blue is likely from StaBil and green is probably from Volvo-Penta stabilizer.

If possible, find out if the fuel filter(s) has/have been changed.

[Stevensc]

JimN, Thank you. It's obvious that you do know your stuff as waterlogged said. No another question. I have the boat on the trailer. The water intake is covered (sitting on top of) by one of the trailer bunk rails. Am i ok to run the engine just long enough to preform this test without cooling (maybe not the WOT test)? Also, do you know what pressure reading I should be getting at the various stages of the testing? Thanks!!!

[BGcraft]

...on my 95 PS 205 there was a in-line fuel cut-off/peacock behind the rear couch/transom carpeted panel. Found it was about 3/4 open & at higher speeds it was starved for fuel.

Worth a shot.

Be well

B.

[mikeg205]

Check plug gaps... if worn, fuel volume could snuff spark

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[JimN]

Check plug gaps... if worn, fuel volume could snuff spark

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One plug wouldn't be noticeable, I doubt two would make much difference at higher RPM either, if they're spaced apart in the firing order.

I got 186K miles on the original plugs in my 2005 Astro van- quenching the spark isn't something I have heard of unless it was in a FICHT outboard with plugs that weren't indexed. The only reason I changed my plugs and wires is because I had an intermittent sensation that I thought might be ignition-related, but turned out to be a failing flex plate. I'm not the original owner and bought it with about 80K, the plugs are rated for 100K miles but waited so long because it's a royal PITA to do that job. When people asked if I had changed them, I said that I hadn't been drunk enough to want to.

[jpwhit]

The water intake is covered (sitting on top of) by one of the trailer bunk rails. Am i ok to run the engine just long enough to preform this test without cooling (maybe not the WOT test)?

Cooling isn't the issue. The raw water pump impeller is lubricated by the incoming water. Running it without water will burn up the impeller very quickly. So, no you shouldn't do this test w/o water entering the cooling system.

Also the test above idle need to be done in the water anyway. The engine needs to be under load.

[mikeg205]

Remember there is fuel pressure and fuel volume. Cutting out could be a number of issues.

Post pics of plugs.. will be good to see if lean condition.

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[JimN]

JimN, Thank you. It's obvious that you do know your stuff as waterlogged said. No another question. I have the boat on the trailer. The water intake is covered (sitting on top of) by one of the trailer bunk rails. Am i ok to run the engine just long enough to preform this test without cooling (maybe not the WOT test)? Also, do you know what pressure reading I should be getting at the various stages of the testing? Thanks!!!

I didn't see this post- as mentioned, no- it's not safe to run it without water; less for the impeller, more for the safety of the engine.

You can't diagnose performance problems on the trailer because the boat needs to be under load. It just doesn't work.

Check the fuel screen at the fuel pump inlet- if it hasn't been checked or cleaned since the boat was new, it's likely that something is clogging it.

[Stevensc]

i think (hope) i found the problem. I had a leak at the connection of the fuel line to the first filter. I'm thinking that could let air in and momentarily shut the engine down. BTW, i disconnected the water intake hose from it's fitting on the bottom of the boat and inserted a hose in order to be able to run the engine. I checked the fuel pressure at key on, motor off, idle and 2000 rpms. All had thirty psi. Of course i did not want to run it to WOT without a load on it. Also checked the fuel. No water or debris. Hope to get it in the water soon to check out but with holidays, etc it may be awhile. Thanks for the suggestions. I'll let you know what happens.

[mikeg205]

Air being sucked in would do it.


That would cause a lean condition and show up as white ash on sparky plugs

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[JimN]

CHECK FUEL PRESSURE!

If that never drops out, check spark. Those are the two things that would cut power but also, watch the voltmeter- if the voltage drops out, it indicates a problem. Sucking extra air won't cause this problem and it wouldn't be intermittent.

[mikeg205]

CHECK FUEL PRESSURE!



If that never drops out, check spark. Those are the two things that would cut power but also, watch the voltmeter- if the voltage drops out, it indicates a problem. Sucking extra air won't cause this problem and it wouldn't be intermittent.

Sucking air in fuel line would not decrease fuel volume when under load?

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[chrislandy]

Mike, I'd expect to see a drop in pressure if it sucked in air, but it depends where the leak is. If it's after the pump then it won't suck it will expel fuel (under pressure) and if it sucks in from the low pressure side it will cause the pump to cavitate and drop pressure.

If it literally cuts out then my money is on electrical (ECU/sensor/alternator spikes/loose connection/intermittent earthing of a worn through wire in the loom etc) rather than mechanical. If it mildly dies/hesitates/drops then picks back up again then that would point me toward fuel pressure, fuel pump electric connection, blocked tank breather or knock sensor retarding the ignition aggressively.