3.0L Alpha One Cuts Out at Hgiher RPMs

Hey: Have a '95 Searay 175 Sport. 400 hours. Just had annual done, plus new water pump, manifold and elbow. Have taken boat out twice since then and have had same basic problem both times. Boat starts and runs fine on out-bound leg of trip (hour first time; about and hour and ten minutes yesterday). Stopped, anchored and hung out on beach for a couple of hours. When heading home, boat starts fine, but starts to cut out as soon as I gas it and get up on plane. And then degrades progressively--for example, starts cutting out at 3400 RPM. I pull back to idle, and then can run for awhile at 2500 RPM (give or take--just examples). Starts cutting out again--usually within a few minutes or less. Back to idle, back to 1800. Repeat etc...you get the idea. I ended up linmping back to the dock the last 8 miles or so at 12-1400 RPMs--no problems at low RPM it seems. Boat idles fine and usually starts right up. While in the water, could run enginer up in neutral to about 2400 RPM for several minutes with no cutting out. Back to idle, put it in gear and run it up to 2400 RPM--starts cutting out in about 40-60 seconds. Brought it home and hooked to earmuffs--no problems at all--runs smooth in neutral or in gear. Me and mechanic are stumped. Anyone got any ideas at all???

Re: 3.0L Alpha One Cuts Out at Higher RPMs

Re: 3.0L Alpha One Cuts Out at Higher RPMs

Hey: Appreciate all the views, but would have thought that one of you experienced boaters out there would have had some advice or ideas by now.

Here's a little more data: We checked the fuel (did a sample check), checked filter, lines, etc. No change. Last week, replaced distributor cap, rotor and ignition module. Ran the boat yesterday--no change. Boat ran great going out; after an hour stop, started to return home and had same issues. Would not run smoothly over 3000 RPM. Would run OK at 26-2800 RPM with an occassional skip, so at least we weren't stuck out all day. Only difference between morning runs and return trip is temp (a lot warmer later in day--live near Bradenton FL) and water a little more choppy.

We are literally at a loss. I am thinking maybe coil, but anything we do is a guess now. Can start swapping out parts, but that's expensive and a hit or miss proposition.
Appreciate any thoughts at all!

Re: 3.0L Alpha One Cuts Out at Higher RPMs

Re: 3.0L Alpha One Cuts Out at Higher RPMs

Have you tried running it on a remote tank?

Re: 3.0L Alpha One Cuts Out at Higher RPMs

Re: 3.0L Alpha One Cuts Out at Higher RPMs

Jlpippins said:

Here's a little more data: We checked the fuel (did a sample check), checked filter, lines, etc. No change. Last week, replaced distributor cap, rotor and ignition module. Ran the boat yesterday--no change.

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check fuel?? check filter?? you need to test the fuel and replace the filters, all you have done with checking is verify they are there

there is a filter in the pump and one in the carb, possibly more if they have been added since factory

sounds like you are replacing parts without troubleshooting first - that can get expensive

check this out:

http://forums.iboats.com/showthread.php?t=295070

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

Working on setting up an external tank to we can try that this week-end--thanks.

Just to clarify as we seem to have a semantics issue--when I say "checked fuel sample", means we had the fuel analyzed. Ditto the fliters etc. Verified they were clean, operating properly etc. Will trace back thru fuel system to ensure no previous owners dropped another filter in the line--has been known to happen.

Thanks for inputs.

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

When it's cutting out does it feel or sound fuel related or ignition? Any backfiring or anything ever?

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

90stingray said:

When it's cutting out does it feel or sound fuel related or ignition? Any backfiring or anything ever?

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Hey: No backfiring. Just cuts out, surges back a few times then will eventually stop running. Does start right back up. My first thought was fuel, but so far the cause has escaped me.

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

Need a tune-up maybe? Cap, rotor, wires and plugs!

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

Hey: did all the tune up things during annual (month or so ago), cap and rotor two weeks ago. Have not done wires yet, although that's a thought. But why would it run good heading out, and cut out a couple of hours later on return trip? Would wires react to temp increase?

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

Jlpippins said:

Hey: did all the tune up things during annual (month or so ago), cap and rotor two weeks ago. Have not done wires yet, although that's a thought. But why would it run good heading out, and cut out a couple of hours later on return trip? Would wires react to temp increase?

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I've seen wire to strange things, higher rpm, low rpm, misfires etc.. So leading to your problem, fuel or spark!

Re: 3.0L Alpha One Cuts Out at Hgiher RPMs

Jlpippins said:

Hey: did all the tune up things during annual (month or so ago), cap and rotor two weeks ago. Have not done wires yet, although that's a thought. But why would it run good heading out, and cut out a couple of hours later on return trip? Would wires react to temp increase?

Click to expand...

I have been having the same issue now for almost a year. I did what you did by unsuccessfully testing systems and throwing parts at it. I have replaced everything on the ignition side and rebuilt everything on the fuel side. Still only get 20-30 mins of good run time.

I have been told to investigate "Vapor Lock". Ran with my blower on and with engine cover off and I got maybe 10-15 minutes more run time out of it. Been in the 90's here too. Here is my thread if you want to go through it. Maybe save yourself a few bucks by not replacing a good part.

http://forums.iboats.com/showthread.php?t=483893

My vapor lock thread.

http://forums.iboats.com/showthread.php?t=485011

Prob won't solve anything but I am hoping to find a solution soon and don't want to keep posting about the same topic. Let me know if you get yours up and going strong!