What's this about?

Discussion in 'Boating Discussion' started by Outlawman, Jun 25, 2010.

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  1. Outlawman

    Took the boat out of DP for some fishin' today, but this is not a fish report. My boat is a Skip 28 with twin Volvo 350's and 280SP outdrives.

    I ran about 5 miles W to look for paddies as I was headed S to the Barn Kelp. 1/2 way there I crossed paths with a large yacht so I slowed from my cruise rpm of 3400 down to about 2000, reset the trim tabs to bow up, crossed the wakes then went to get back on plane. In accelerating back onto plane again the starboard engine / outdrive wasn't performing like normal and seemed to be cavitating with variable rpms. But the port engine and outdrive ran flawless all day.

    So I did just about everything could to eliminate what seemed to be cavitation. In neutral, the engine would run fine. In gear, the engine would be inconsistent in rpms and wouldn't run like the port engine. So I had to cruise at about 1200 rpms over towards the San Mateo Kelp. With a mile to go, I tried it again, and it ran as it should have, back up to 3400 rpms and all was fine. And after spending hours there fishing on the hook, we decided to head on back. Both engines ran perfect for the 8 mile return trip to DP harbor, then upon backing down to 1200 - 1000 rpms on entering the harbor, the starboard engine started again, then dropped rpms and shut down. I started it back up and it ran with inconsistent rpms again, and I put it back in the temp slip I have been renting for the time being.

    About 6 weeks ago I pulled the engines to pull my fuel tanks and put in a new main tank, then reinstalled the engines. I've used the boat for a couple similar trips between today and the new fuel tank work without issue, and that's why this is puzzling. I was expecting that if there was a problem, it would have shown up previously.

    Anyone ever experienced something like this and understand what's going on here, or have anything to offer please?
  2. Staged

    Something in your fuel delivery system and I don't mean tank or filters, I know you've got that covered. Start with fuel pump and check fuel pressure, then on to carb, from what you described the carb would be my best quess.
  3. Fishbones

    Make sure you vents for the fuel tanks are clear, kinks, water or fuel caught in the down side of a loop.
  4. Alan

    Agree with above but I think you could add electric/distributor issue with some h20 to the list. I say that because it is intermittent. Also a possibility of some sort of air getting into the fuel delivery.

    Good luck,

  5. Outlawman

    The fuel system is new everything...tank, filters, hoses, valves, you name it... except for the mechanical fuel pump, which I rebuilt (new diaphram). I will check the system and see if something shows up as the culprit.

    That's doesn't seem likely, but heck, anything's possible. Thanks for the suggestion.

    The vents have been checked and rechecked many times prior to the new tank, and after the new tank...

    that said, I'll do it again... :imdumb:
  6. piperca

    David, two words ... "Viking burial!" I'll supply the gas and we can do mine and yours at the same time! :rofl::finger::rofl:

    Seriously, it sounds like you need a mobile mechanic to help you troubleshoot. Try giving John Von Der Ahe a call at 949-689-5752.

    prop hub is spun. engine off, put the drive in gear and see if you can turn the prop by hand. always buy michigan wheel props, the oem volvo props suck.
  8. piperca

    Rick, I don't think a spun prop would cause the engine to shut down ... correct me if I'm wrong!
  9. Outlawman

    Nope, but you can join me while I sit on mine drinking a cold one watchin' the show...[​IMG] :finger: [​IMG]...

    Sure, if I don't figure it out, then yes, my mechanic will take a look. But here is my process: if I don't know, I ask, then I do it if I can, if not, I hire a pro.... pretty much what most all of us here do I believe.

    I've never had a spun prop, but if it was spun, would it allow me to run full speed after being spun???

    Good point. Based on the prior posts above and my experieces last year with fuel issues before the new system/tank, I'm thinking fuel, possibly filter, etc... hopefully minor.

    I'll look into all of it later today. Thanks.
  10. piperca

    David, I have had a spun prop and you can't get the RPMs up at all ... well, you can, but the boat doesn't go anywhere.

    To rule out the fuel issue, can you swap the fuel feeds to each engine and run her that way to see if it affects the other engine? That would cut out a lot of fucking around if it doesn't. If it was vent related, it should have affected both engine, since there is a common vent to the single tank. How about running the engines off the alternate tank?

    How were the gauges looking on your run in? Temp?

    You've probably thought of all of this, but I'm just throwing out suggestions. I feel for you ... this must be very frustrating.
  11. Outlawman

    Yep, that's what I thought.

    I'm heading down there soon to check things out...

    Gauges were normal, other than the variations in rpms

    You know, after what I've done and been through to get where I'm at, it's just another day... LOL... I believe this is just a minor fuel filter issue, probably nothing more.

    I was worried as my friend who was with me suggested the possiblility that this engine possibly didn't get reinstalled correctly due to something about the flywheel plates, spline, etc.... I thought it was done right and everything seemed to go smooth and buttoned up nicely, but it made me wonder if I might have to pull that engine and reinstall it... but I don't think that's the problem here.
  12. wils

    I vote for the engine being installed backwards....

    but seriously, I like the suggestion about switching the fuel lines to the engines.... even if you have to temporarily jury-rig a couple of rubber fuel lines.
  13. Staged

    My money is on the carb.....filter, float/needle & seat, choke< double check that one...good luck
  14. Outlawman

    Thanks Tom, will check it out. Was hoping today would work, but now it looks like tomorrow AM.

    Tight lines [​IMG]
  15. piperca

  16. Outlawman

    Was finally able to get down there this afternoon, drained the fuel filters, all good, started her up and took 'er out of the harbor for a spin, up to 3400 rpms for maybe 1/2 mile, then back into the harbor cruised around at 900 (5 mph) for a while and back into the slip... no issues... go figure!
  17. piperca

    Fucking boat!
  18. fish doctor

    ground wire?
  19. Outlawman

    ... :confused:... care to elaborate?
  20. scwafish

    I would guess what he is trying to say is most here today gone tomorrow issues (intermittent and unrepeatable) are generally electrical and not mechanical. Check grounds, and ignition modules and/or components if it starts giving you crap again.