Carburetor issues

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by Sea-Ya, May 14, 2018.

  1. Sea-Ya

    Sea-Ya New Member

    12
    Sep 29, 2016
    Long Island
    2004 Sea Ray 215 Express Cruiser
    5.0 Mercruiser
    I took her out today for the first time this season. I have a 5.0 Merc with a 2 bbl carb which was rebuilt at the beginning of the 2017 season due to ethanol issues. I always use Startron at every fill up and for the winter storage. Today at first she ran smooth. Got up on plane and ran flawless at 3400 Rpm. I even brought it up to 3800 with no problems. As I was pulling back on the throttle when I got under 3000 she started to bog down. The rpm's were fluctuating between 2500 and 2800. When I tried to go higher it bogged down. I pulled it down to around 1000RPM and it was still fluctuating. At one point it did stall out on me. I got it started. As I gave it throttle it would bog down but then at one point it ran smooth and ran fine again at 3400. I pulled back again and the same thing happened. I got it down to the point where it would idle and I got it back to the marina. Could I have water in the gas? I was going to pull the fuel water separator off and empty it out and see if there is water in it. Or could I be having some sort of carb issue again? Any input would be greatly appreciated.
     
  2. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    absolutely both of those could be your problem. Crap in the tank, clogged anti syphon valve, fuel pump ready to check out.
     
  3. Espos4

    Espos4 Active Member

    509
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Ethanol issues......What other parts of the fuel system were replaced?
    New fuel lines? New fuel tank?
     
  4. Sea-Ya

    Sea-Ya New Member

    12
    Sep 29, 2016
    Long Island
    2004 Sea Ray 215 Express Cruiser
    5.0 Mercruiser
    Nothing else was replaced just the carb. Last year it wouldn't idle under 1500 Rpm's. The mechanic said the ethanol screwed up the carb and when I throttled under 1500 the carb kept dumping fuel in and was flooding itself out. After the carb was replaced it ran fine all last season.
     
  5. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Your going to have to clean your fuel system from tank to carb.
     
  6. Espos4

    Espos4 Active Member

    509
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Ethanol issues in older boats can be very problematic.
    Basically any varnish or buildup in the fuel system that accumulated over the years was scrubbed off by the ethanol and sent down the fuel line.
     
  7. BillK2632

    BillK2632 Well-Known Member SILVER Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    Start at the tank, check the pickup, anti-siphon value (those are probably ok) , fuel feed line, fuel filter, carburetor inlet filter (probably not ok). I had ethanol induced problems a few years back - rebuilt the carburetor. BUT, the real problem was ethanol had deteriorated the fuel feed line from the inside, it looked fine outside, but the inside was crumbling into tiny little pieces. These were making it through the water separating filter and eventually into the carburetor. The fuel I poured out of the filter looked like someone had sprinkled pepper in it. At 14yrs old you are due to replace the fuel lines, I would also replace your vent line and fuller hose.
     
    Last edited: May 15, 2018
  8. rondds

    rondds Well-Known Member SILVER Sponsor

    Oct 3, 2006
    Jersey Shore
    2001 380DA
    Merc 8.1s (2008)...Hurth ZF 63 V-drives...WB 7.0 BCGD (2013), Garmin 8208 & 740 MFDs, GMR 24xHD dome
    Do you have a spin on fuel/water separator filter? Dump out the gas, fill it 1/2 with Seafoam, 1/2 with gas. Put it back on and start the engine and run it for 5 min. Shut down and let it soak overnight. Solved a similar issue with my generator. Might work for you and it's cheap and easy enough to do.
     
  9. Sea-Ya

    Sea-Ya New Member

    12
    Sep 29, 2016
    Long Island
    2004 Sea Ray 215 Express Cruiser
    5.0 Mercruiser
    I went down there this morning before I read all the above responses. I pulled off the fuel water separator (yes spin on) and dumped the gas into a glass jar and the gas was clear. Had no water in it and no particles. I even showed it the mechanic there and he said it is good. I didn't have enough time to diagnose further but I think the carb is dumping fuel in the carb like last year. I had started it and when it bogged down and stalled it sounded like gas was still be pumped in the carb for a second or two. I will have to check further. I also never thought of changing the fuel lines but that does sound like a good idea.
     
  10. rondds

    rondds Well-Known Member SILVER Sponsor

    Oct 3, 2006
    Jersey Shore
    2001 380DA
    Merc 8.1s (2008)...Hurth ZF 63 V-drives...WB 7.0 BCGD (2013), Garmin 8208 & 740 MFDs, GMR 24xHD dome
    I had no water or particles either. I collwct the gas in a clear plastic bottle and run it through a coffee filter. Happened last spring and this spring at commissioning.
     
  11. Sea-Ya

    Sea-Ya New Member

    12
    Sep 29, 2016
    Long Island
    2004 Sea Ray 215 Express Cruiser
    5.0 Mercruiser
    Now that you mentioned sea foam, I have been reading a lot about it tonight. I always use Startron for my additive in my gas. Do you have a preference of which one to use? Would Seafoam keep the carb cleaner than Startron over the winter storage or even during the season. I always use Startron additive due to the ethanol at every fill up. Just wondering if Seafoam is better.
     
  12. rondds

    rondds Well-Known Member SILVER Sponsor

    Oct 3, 2006
    Jersey Shore
    2001 380DA
    Merc 8.1s (2008)...Hurth ZF 63 V-drives...WB 7.0 BCGD (2013), Garmin 8208 & 740 MFDs, GMR 24xHD dome
    I have been using Startron since e--10 became a thing, and always with the appropriate dosing, usually on the side of adding a bit extra. I've never had an issue with the mains on this boat or my previous one (and that covers a span of 9 years ). The only issue I've ever had is this hunting thing, with this generator (which is not even 5 years old) and only at spring startup, and only the past 2 springs

    I don't know the answer to your question, but I know that I will winterize with Seafoam in the gen filter this coming fall. In the spring of '19 I'll start the thing up and if it hunts, I guess I'll do it again.
     
  13. BillK2632

    BillK2632 Well-Known Member SILVER Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    What led me to the fuel lines being the issue is my engine would bog down and stall occasionally and was hard to restart. This got worse and to the point where sometimes it would not restart until it sat for a few hours. Acted a lot like vapor lock. When I checked the filters that is when I found the debris that was the inside of the fuel line. Next I opened up the carburetor and it was a mess inside. What was happening was the fuel line was deteriorating from inside letteing debris into and through the filter to the carburetor - I'm sure the ethanol was doing a number to the carburetor also, float was a mess. The bogging down and hard start I finally figured was the fuel line would collapse at higher RPM effectively shutting off the fuel supply (there is quite a bit of suction on the fuel line). It would restart after the fuel line opened back up.

    If it were my boat I would:
    • Replace the fuel feed line (I would do the vent and fill also, but you can do that later). Pointless in doing anything else until you know the fuel line is good. Go to West Marine or somewhere and get the J1527 Type A1 rated hose should have the same thing stamped on your current hose.
    • While you are replacing the fuel line, check, clean or replace the anti-siphon valve and pickup. Make sure the pickup can't suck air after the tank level goes below a certain point - think a hole in a drinking straw.
    • Replace the fuel filter
    • Replace the carb inlet filter (if it was replaced when you rebuilt, at least check / clean it)
    • Clean the carburetor good - just use a carb cleaner spray - do the SeaFoam treatment if you want - good stuff and it can't hurt.
     
  14. Sea-Ya

    Sea-Ya New Member

    12
    Sep 29, 2016
    Long Island
    2004 Sea Ray 215 Express Cruiser
    5.0 Mercruiser
    Ok, thank both of you for your responses. I am going to take the carb off and see how that looks and then also check in the fuel lines. I was talking to another boater yesterday and he said these 2 bbl carbs are notorious for having problems all the time.
     
  15. BillK2632

    BillK2632 Well-Known Member SILVER Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    Do you have the 2bbl Mercarb? That's what I have - mine has given me no trouble since I rebuilt it 4yrs ago - I have not put a drop of ethanol gas in it since then either. I personally found it very easy to rebuilt and get it setup and running properly. There is a specific process to adjust these carburetors, but as carburetors go they are about a simple as they come.

    http://www.boatfix.com/merc/servmanl/18/18b5r2.pdf
     
  16. Sea-Ya

    Sea-Ya New Member

    12
    Sep 29, 2016
    Long Island
    2004 Sea Ray 215 Express Cruiser
    5.0 Mercruiser
    Yes that is the carb that I have. Unfortunately I have no choice but to use ethanol gas here. I do treat the gas all the time. I am very handy and have worked on engines before but the one thing I have never done it rebuild a carb.
     
  17. BillK2632

    BillK2632 Well-Known Member SILVER Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    I had never rebuilt one by myself until this one - had helped my father rebuilt the Holley 4bbl on the Correct Craft but that was it. This is a good resource. I bought my rebuild kit here and followed their instructions and watched the youtube videos. Not saying you need to rebuild again - my guess is the float/needle is gummed up from sitting over the winter and it just needs to be cleaned and adjusted again.

    http://www.carburetor-parts.com/Mercarb-Marine-Troubleshooting_ep_482.html
     
  18. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Lots of boaters use ethanol as an excuse for their poor running equipment, when in fact it's just poor maintenance causing their problems. Consider that probably more than half the boaters in the US have no choice but to use ethanol fuel, and that Mercruiser says their engines are safe to run on 10% of it.

    What can happen if you run the 10% on a boat that has been run on non eth for several years is it will loosen up the deposits that have accumulated and start plugging stuff up. All good points mentioned above, but you need to start by cleaning the fuel tank first. Your headaches will continue until the entire fuel system is clean.
     
    dwna1a likes this.
  19. Loyd Dinneen

    Loyd Dinneen Member

    252
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Rebuilding a 2bbl carb is really simple to rebuild I did mine and it was the hard starting issue fixed it right away. Mine was a rochester with two needle valves a mercruiser has one needle valve. To get back to your problem it sounds like your float is sinking, stuck or out of adjustment. As for seafoam it is the only product. Use it for winter storage and for keeping my system clean. I know this is a old post but others may find it helpful.
     

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