Hesitation on WOT despite float adjustements

Tested my '64 40HP Evinrude Big TWIN, and still am experiencing hesitation and bogging while approaching and near wide open throttle.<br /><br />It'll idle around at low speed just fine indefinately, responds quite good (as compared to earlier) right out of the hole.<br /><br />BUT, as after it planes out and runs a bit, it just bogs way down, then after a moment it'll either catch back up on it's own, or I'll idle back and to match the reduced RPM's and fuel need.<br /><br />I suspected the carb float adjustment to be at fault (the carb was just cleaned and rebuilt)...I didn't mess w/ the needle adjustment, figuring that was only applicable to low idle which runs fine. The first time I took it out, this bogging near WOT happened w/in 2-5 seconds.<br /><br />So, I took the carb apart to reinspect the float...it looked like it was nearly right, but, just to be sure (per the manual's guidance) I made very certain to set the float itself, level w/ the body/bowl.<br /><br />Put everything back together and on the water, and now, though it runs much better, it still will do basically the same thing, but this time not as bad a loss in power, and after about 20-30 seconds, not 2. It recovers more quickly...but nevertheless, I know it's still not right and this is something I'd like to get right before towing people.<br /><br />It responds as though it's a fuel delivery problem...things are clean, bulb firm, plugs cleaned, gas is two weeks old.<br /><br />What's the next plan of attack?<br /><br />Should I just raise the float a bit beyond level and hope that permits enough fuel to remain in the carb bowl?<br /><br />Beofore the carb rebuild, when I primed w/ the bulb, after it got hard, it would squeeze fuel past the needle, as the float wasn't set properly to close it...despite that improper adjustment before, the motor never became starved for fuel.<br /><br />Figure it's the carb or high speed jet...but since the float level has led to improvement, maybe I should keep on "bending the tab" till it nearly leaks when primed???<br /><br />Is that ok, any ideas? Thanks

Re: Hesitation on WOT despite float adjustements

Surging at wot is almost always caused by fuel starvation. I would check the fuel pump. Have someone pump the bulb when it is doing it and see if that helps. Also check all the lines from the tank to the motor for restrictions, kinks, an old filter or air leaks. Then check the tank vent. If all checks out change out the fuel pump.<br /><br />I would not keep running it like that cause leaning it out you will be putting pistons in it soon.<br /><br />Look hard at the fuel system and you will find the problem<br /><br />The motor is not that sensitive to float adjustments. I think you are ok in that dept.

Re: Hesitation on WOT despite float adjustements

Where in NJ are you? <br /><br />Brick NJ, here

Re: Hesitation on WOT despite float adjustements

I agree with Jon... look for leaks in the fuel lines... wipe grease on all fittings ... If you don't have the surging/bogging then start wiping grease off... on fitting at a time. Eventually you should find your leak. Don't forget around the bowls as well.... <br /><br />Glad to see it's back on the boat and runnin for you. Little tweaking and it should do great.

Re: Hesitation on WOT despite float adjustements

Did you completely disassemble the carb for cleaning and blow out all passages with high pressure compressed air? You did say that - - " I didn't mess w/ the needle adjustment"????

Re: Hesitation on WOT despite float adjustements

Yes, the carb was completely dissasembled, soaked, and all passages blown w/ compressed air before reassembly (the not messing w/ needle adjustment, I was referring to after having set the needle, which is for low idle, I figured that turning it while experiencing the fuel starvation problem at WOT would have no bearing, so I left it)...but the carb is "sparkly clean", so I don't think anything is gummed up.<br /><br />I live in Princeton Junction, NJ...but the boat resides near Norwich, CT (Griswold...Pachaug Pond).<br /><br />Per advise, I will check for leaks again...but there were some things mentioned, that I think I can rule out...<br /><br />The fuel pump I replaced w/ a new one when I first started fiddling w/ this project 3 years ago as I recieved it w/out one (since that time, it's only been used a half dozen times)...so I'm hoping not to fork over another $50 (unless the diaphragm alone can be replaced)...in either case, this is a problem new to just this current time out (hadn't experienced it prior to today...but who knows, coincidental failures seem to happen all the time).<br /><br />I will replace the fuel lines and reclamp tight again...cheap enough remedy to rule those out.<br /><br />Finding a "test partner" to run along w/ me is difficult at best, since I can't guarantee they wont be towed in by me swimming (again)...but I did try pumping the bulb up while running (but again, for safety, I wasn't trying this at WOT...so hard to really tell if it had much affect).<br /><br />Tank vent seems fine...nothing plugged at top, plus I figure w/ the fill cap unscrewed a bit, plenty of freedom of air movement w/out creating a vacuum.<br /><br />The THING that PUZZLES me MOST...is that so far as I can honestly tell, my adjusting the float just a bit higher, did make a SIGNIFICANT improvement in the way it ran, over the way it was previously adjusted (now, admittedly, I don't know if that just turned out to be coincidence, or just me retightening during routine reassembly, and inadvertently snugging something up just a bit more)...the difference went from "no way can I take someone out in this"...to, "so long as I throttle attentively, I can get close to WOT w/out starving"...an improvement nevertheless.<br /><br />I'm trying to isolate the problem...but at the same time, each try usually means pulling the boat and trailering back (a short trip, but given the situation, the best bet rather than working on it at the launch)...I think, in addition to performing what's been suggested, I'm going to see if the float can be tweaked a bit more (since the only thing that has changed prior to the carb rebuild and now, aside from cleaning, is float level, and retorquing of the carb fuel hose, and carb bolts).<br /><br />I'm getting closer...thanks for the help, almost there (except for the occasional "kick" from time to time...but one problem at a time, and I'm thinking what I'm hearing is more mechanical than a fuel issue)...again, things keep popping up each time I address something (and I use this thing so infrequently, it's difficult to really say whether or not the problem was there before)...just trying for one weekend of "semi-trouble free, moderately OK running" use...(I managed that once so far this year) doesn't have to be perfect (figured it was abandoned and left for dead for a reason...so I can only justify getting it running "well enough").

Re: Hesitation on WOT despite float adjustements

had the exact same fault with my 89 60hp vro.make sure all the fuel lines from the tank to the pump are a good fit and are the correct size for the fuel pipe being used.as the fuel line from the tank to pump is under vaccum it will suck it air but may not leak fuel remove all fuel pipe fittings from hose and check for splits down inside of hose and cut back hose by 1 inch and refit use the plastic ratchet clips as worm drive clips will not clamp down in a even circle and go oval causing air leak cable tie will not go tight.check primer bulb for leaks,put fingers over ends and hold under water and squezz if you see bubbles its shot,check the one way valve works as you should only be able to blow throgh it one way.i had to fit an new pump aswell!

Re: Hesitation on WOT despite float adjustements

My motor was running great then yesterday , very similar problem . I corrected temporarily on lake but when I got home I found a caterpillar in my vent hose, as well as a sticking fuel tank check valve . spring and bearing are now in Davey Jones locker. lol<br /> I'd check all lines make sure there clear , filters, water seperator, etc. My problem was hardly noticable at first , then got worse pumped bulb better for a good bit then lost power. Opened fuel cap fixed, odd the way it switched from good to bad . I guess the caterpillar was a dancin, lol<br /> <br /> Good Luck,<br /> KYHunter

Re: Hesitation on WOT despite float adjustements

Just thought I'd mention, I just take fuel line off tank and sqeeze bulb letting the open end of fuel line suck to my finger . It'll stay as long as you want if the check valve is good.<br /> I Think,<br /> KYHunter

Re: Hesitation on WOT despite float adjustements

Getting REAL FRUSTRATED now...spent the $ and things got WORSE...seriously, if I can't get this project going by the end of tomorrow, I'm pulling the plug as I drift out, and will scuddle this nightmare of mine.<br /><br />Now, I can't even get it to fire up!<br /><br />What I did...I tested the 3 year old fuel pump by removing the plug wires and disconnecting the fuel outlet from the pump, pulled the cord...got some fuel out, but decided to inspect things...<br /><br />...making a long story short, I ended up spending the $50 on a new fuel pump (reusing the old one is no longer an option). I also replaced all the fuel lines (not too much to begin w/) checked the connections, and even treated it to a new bowl filter...<br /><br />I figured, w/ those simple replacements, there wasn't too much to screw up...I didn't touch the carb at all, or the plugs.<br /><br />Scurried on down to the pond as it was getting dark. On the 2nd or 3rd pull, it did briefly fire, but after that, nothing at all, no firing, no starting, no running, no luck or fun at all (figured I'd test it in the dark, rather than risk waking to a disappointment in the morning).<br /><br />I initially started w/ the choke on automatic, since that's where it always seems to start (and could never really determine when or why to use the choke ON or OFF positions...any explanation?)<br /><br />I pulled the cord till my fingers literally bled after the blister formed...quietly drifting out.<br /><br />Only good thing is I didn't have to SWIM back (because I brought a paddle this time).<br /><br />I'm assuming things flooded? I don't really know...I suppose it could be another one of those coincidences that despite the rebuilt carb, and replaced fuel pump, now the ignition system mysteriously simultaneously went out...I'll check for a spark in the morning.<br /><br />So what's one to do in this situation...just pull it out and wait...how long, w/ the carb doing what? I pulled the plugs, as best I could tell, in the dark and hanging off the back of the boat, they didn't look wet.<br /><br />I find it unlikely that something else critical just happened to go bad now...how long could the streak continue.<br /><br />BUT, other than patience, and trying the same things again tomorrow, any advice at all on how to get things going again.<br /><br />It's come full circle, and gone from working at about 90%, then after "improvements", not at all...frustrating to say the least.<br /><br />I'll sell anyone the "SEA SNOT 2" pretty cheap right now...but make an offer before I pull the plug and sink it!<br /><br />I'm thinking, that at this point, it can't be the bulb or pump, since I can get gas to the carb...and how much do you really need to get it to fire.<br /><br />Stumped, broke, tired...I hope everyone's boating experiences this weekend, are more fruitful than mine have been. Thanks again for any help =(

Re: Hesitation on WOT despite float adjustements

Alex - Seems like you are chasing fuel as the source of the problem. Have you checked spark with a spark testor? You should get a bright blue snap that will jump a 1/4-3/8" gap. I don't remember if that engine has points & condenser.<br /><br />You can troubleshoot the fuel system by putting some premix in a spray bottle and with the engine cover off spraying directly into the throat of the carb.

Re: Hesitation on WOT despite float adjustements

The motor does have points and condensor (though the points looked pretty good, I cleaned them up in NJ w/ fine paper, and regapped to specs).<br /><br />I've not checked w/ a spark testor yet (primarily because up till now, I figured if it started up and ran on the first pull, then the ignition system was working ok)...plus, pulling the starting cord and checking the plug at the same time alone is a task I've set tomorrow aside to master.<br /><br />Just two days ago...I took the boat w/ motor out, in and out of the water 3 seperate times, all starting on the first pull, and ran for a 1/2 or so total, never stalled...ran fine except for at WOT...could it still be that there is an issue w/ the spark and ignition system, and I've just been lucky to get by so far even though it's weak?<br /><br />If I can get it to fire up...which it usually does...then I'm good to go...it's when I pull it and it doesn't start, that I'm not really sure what to do next...so I pull and pull...yet it doesn't start.<br /><br />I think I'll try it in a test bucket in morning, if it fails to start, I'll check for spark...and if that seems ok, I'll remove and/or inspect and shake the carb...if I get it to run for a minute just once, I'm sure it'll start fine and run all day...but who knows.

Re: Hesitation on WOT despite float adjustements

ALL CHECKS SEEM OK...but STILL no luck, so now what?<br /><br />I triple checked things...it still doesn't fire now.<br /><br />Disassembled and blew out the carb air passages.<br /><br />Turned the motor over w/ plugs removed from block, and left on wires, and I get a visible blue spark (nothing huge, but enough to easily see).<br /><br />Could a "weak spark" be the cause...or more importantly, how does that just happen one day.<br /><br />Hopefully, something else more simple and free is out of whack to adjust...but I don't see/know what.<br /><br />When I pulled the flywheel, everything on the armature plate looked ok...do things under there degrade slowly, or just fail completely.<br /><br />Was hoping not to have to spend money under there, since prior to several days ago, getting it started wasn't an issue (and I've not tampered w/ the ignition system since it worked).<br /><br />I'll try a few more pulls...but after that, I think at sunset she sinks (meet me at pond's edge if you want her)...I'm just about done w/ this thing.<br /><br />I did try spraying the fuel mix through the carb...but no change.<br /><br />So, now, problems point to the ignition system...besides a blue spark at the plugs, firing at the right time...what else do you need to get it to start up?

Re: Hesitation on WOT despite float adjustements

A GLIMMER of HOPE!<br /><br />Finally, w/ the aid of spraying the fuel mix directly into the carb, it fired and ran...then did so again after being started in the same manner...but after about 30 seconds, that was it.<br /><br />Nobody said I had to pull the cord 100 times...but that seemed like the magic #!<br /><br />So, seing that the lines are new (maybe some cutting or debris came along w/ them), and that the bulb and pump are new and clearly move fuel...the blockage would seem to be somewhere in the carb...but where?<br /><br />I've already disassembled it and blown it out again umpteen times, and I still haven't gotten it to move fuel, so where do I look?<br /><br />The float bowl fills just fine each time...I'm fairly certain that the small holes under the cap plug for LS idle are clean, can't really see them getting plugged in a few minutes run time (and they were clean before the rebuild as well).<br /><br />Now it's just a repeat problem...can get it to fire and not run (well, at least I established that the ignition system was ok, so thanks for the help w/ that).<br /><br />What a lesson in troubleshooting...but I've get to get it unplugged...any way to test where fuel should be popping up or out of the carb when the motor is turning.<br /><br />I figured if I knew where to look, I could pull the plug leads, and while pulling the cord, see where what fuel is sent through the system by the pump diaphragm, is supposed to get into the carb (or come out of it actually).

Re: Hesitation on WOT despite float adjustements

Any IDEAS...anyone (plug's coming out in 59 minutes).<br /><br />I've tried all the things that make the most sense, and still can't get this motor to run again w/ the carb on.<br /><br />The fittings are tight, gas readily gets to the carb bowl...if I remove the float/needle, gas readily comes out the overflow (2) areas.<br /><br />The compression in the cyclinders adequately operates the diaphragm in the fuel pump, you can see the gas pulse out the end of the hose.<br /><br />BUT, whenever you hook it up, it just never starts.<br /><br />If I spray fuel mix through the carb...she fires.<br /><br />If I remove the carb, and spray fuel mix, she fires.<br /><br />The carb is clean, no doubt about it...it wasn't grungy before the rebuild, worked just fine a few days ago.<br /><br />I've taken it all apart about a half dozen times today...there's not much in there, all the parts are in place, and the only thing to really adjust is the float, and I've tried that in a variety of ranges since it stopped working, but it has no effect, nor can I see how it would have much on starting, having now become intimately familiar w/ the way the carb works and all the jets and passages.<br /><br />None of the passagesways ever seemed clogged...I sprayed them w/ carb cleaner and let it soak, repeated the process several times, blew it out w/ compressed air a bunch of times...clearly, there is no blockage at all, so why wont gas get sucked into the motor through the carbs like it did the other day (and every day prior)?<br /><br />I'm beginning to think that what my motor needs, is a new motor...this thing just isn't making any sense, and there's not a whole lot else I can see to do to it that would make sense and make it run.<br /><br />I try to be optimistic...but maybe the carb has just exceeded it's usefulness...can't fully understand how (poor running, I could accept, but not starting...when the ignition checks out, why oh why?)<br /><br />I'm always checking up for a suggestion...and have a light ready if it comes to working on it in the dark.<br /><br />Had at least, at this point, hoped to run it to winterize it...since for me, I'm about out of time for the project this year...it's given me nothing in return...<br /><br />Just venting at this point I guess

Re: Hesitation on WOT despite float adjustements

You haven't mentioned the needle setting. That's the only thing I can think of at this point. If it has fuel in the bowl and it fires when you spray gas in, there had to be some kind of blockage. I'd work more with the mixture needles. It's possible that the packing is in crooked or something else is blocking the fuel from getting from the bowl into the cylinder.<br /><br />Good luck.

Re: Hesitation on WOT despite float adjustements

The needle setting has been adjusted ad infinitum.<br /><br />There is only the low speed idle needle that is adjustable (wherever the high speed needle is, it's fixed).<br /><br />Initially...since it was working fine, I didn't tamper w/ the needle...just replaced the fuel lines, filter, and pump.<br /><br />Since then, I've completely disasembled things a few more times...the packings are all fine, nothing chewed up at all. There is the aluminum threaded insert, followed by the packings, then the packing nut, and finally the needle.<br /><br />I just can't figure this out at all...I have assured myself that there is absolutely no blockage (at least detectable).<br /><br />Just to convince myself, I sprayed a full can of carb cleaner through every orifice, to be certain it cam out fine where it was supposed to.<br /><br />As I can best tell, the way fuel actually works it's way through the carb...from the bottom of the bowl, up through the "L" shaped passegway, in and alongside the upper body of the carb, back towards the rear of the carb. Then there are the series of small holes in a semicircle, w/ 2 slightly larger ones, that affect the LS needle adjustment, and the needle itself.<br /><br />I spray the cleaner in, and see it freely shoot out of all the tiny holes...same thing when I blast the L...there just isn't anything blocked.<br /><br />I always attempt starting her up w/ the LS needle backed out 1 1/2 turns...I've also tried it everywhere from lightly seated, to all the way removed...to everywhere in between...and it's never any different.<br /><br />I can fire it up w/ a spray mix, and keep it going so long as I spray, for a minute...till I get tired of it...but, it never does it itself.<br /><br />I even tried starting it in gear at higher throttle, to see if I could get the high speed jet to take over...same scenario, I can get it to fire on the first pull if I spray mix on, but it'll never run on it's own.<br /><br />In lieue of any suggestions, I think for Christmas, I'll ask for a carb that isn't dead.

Re: Hesitation on WOT despite float adjustements

Ouch! I just sold one on Ebay for way less than it was worth. <br /><br />I'm no expert on these, but I think the high speed needle is behind a plug of some kind that you can drill out. It might be worth a shot, if you have access to a replacement plug. The only other thing that might cause this would be a lack of bowl venting. If there's no vent and the fuel inlet valve is closed, you won't get any gas. It does sound like a mystifying problem!

Re: Hesitation on WOT despite float adjustements

I figure...I can always find something to jam/plug up a whole I make...but I'm thinking the HS jet really shouldn't have any bearing on my inability to get things to fire...soI'm not ready to drill and inspect just yet (honestly, 2 days ago, this thing ran the best it had in 3 years...now nothing).<br /><br />The vents are free as well...basically the central brass tube that projects through the body of the carb, and seals inside the round opening in the carb bowl, w/ the round felt/cork seal between the mating surfaces...if I hold it at the right angle, I can see all the way through it...as far as orifices in the carb go, it's pretty big at 3/16" ID or so...but not plugged up. There is also another venting place, a whole located just to the right of the LS needle valve adjustment...all things check out, nothing plugged, air blows through fine...so does carb spray.<br /><br />I was thinking, that if somehow cyclinder pressure was drastically reduced, then maybe there wouldn't be enough vacuum created to suck fuel in and start the venturi process...but I'm also thinking, if that were the case, why would it even ever be able to fire at all, and how could it change from one day to the next, all of a sudden, especially w/out some sort of major mechanical fault (which did not happen, since it ran fine one day, and then after adding the new components...which also check out fine, and work off the vaccum created).<br /><br />I know on the cars carbs I've worked w/...there was always a plunger activated by the linkage, that created the fine mist to get things to fire...this carb on the boat, seems a lot simpler, and as best I can tell, gas just sort of wiggles it's way through the holes in the top of the carb over the LS needle, and gets sucked in by vacuum.<br /><br />Perhaps one more day of attempts at this...but I can only disasemble, soak, clean, inspect, and reasemble so many times...before I come to realize that the problem might be more than can be rectified by traditional means (I had it running great for one day...alas, but nobody was around to belive it!).<br /><br />I've tried setting the float from anywhere above, below, and on level...w/ no change...

Re: Hesitation on WOT despite float adjustements

I know things are pointing to fuel at this point but just for the hell of it replace the points & condenser. It would take less time to replace them than you have already spent typing here. I'm thinking that while your plugs may be firing they are firing too weak to get a good apark. Did you do the spark test I recommended?