insanity looming over non starting boat

[sweebs]

Well I just looked at my boat, access to the anti siphon valve will require pulling the carpet and cutting out the floor, so yeah, feeling foolish for not parting this thing out back in June when the boat shop told me the engine was seized


new info: I looked at the carb before trying to start again today, the choke plate was wide open and It's a brand new choke installed in same position as the old, with the same spring winding and location as the old,, anyway, I readjusted choke about 90 degrees anticlockwise so there was about a 1/16" opening. Cranked the starter - no starting fluid, no gas poured down carb's throat, and voila! She started right up! Ran at about 2000 rpm for a few minutes, I could see gas going into carb, when I throttled down to try and get to a more of an idle speed, she died and now won't restart. When I had my son pump the throttle lever, I could hear the accelerator pump moving up and down but could not see any gas squirting. Shouldn't gas squirt into the throat of the carb when the throttle is pumped? When I tore down the carb for the rebuild the video said some carbs have a retainer spring/screen/check ball down in the accelerator pump housing, and some carbs do not. Mine did not, so I did not put those in. Mine has a single hole on the side near the bottom of the accelerator pump housing.

Anyone make any sense out of these symptoms? I now know the motor runs, but keeping it running sure is stumping me! Thanks!!

 

[thekidd77]

If you pull the fuel line off the carb and away a bit and cram a plastic coke bottle over the end turn over the motor, if it starts filling with gas immediately the anti siphon valve, fuel filter and the fuel pump are all good...

 

[sweebs]

thanks kidd,, yeah, not as elequent, but put rag under metal fuel line after removing from carb and immediately upon cranking fuel does pump out of the line, not sure at pressure level, but it does pump out, so I'll leave it as there is no blockage. I'm going to try and increase idle mixture and possibly play with float level (the nitrophyl float had a precise contour and little convex markings to measure from and my new 'better' brass float is more of a rounded shape, so I'm thinking that measurements down to the precise MM/32nd" if measured from slightly wrong spot on float, could alter things a bit).. Man I'd love to be out on the water with this thing instead of sweating balls continuously wrenching on it in the driveway!

 

[thekidd77]

while you have the carb apart again id spray brake cleaner down each jet and verify it comes out the wells that the brass tube down from each venturi sits over, I think those passage ways are plugged on you, id also take the idle mixture screws right out and spray into them too

I can't remember if the floats and needle valves stop the flow of fuel to the accelerator pump, if the accelerator pump isn't pumping then I think that means the carb is completely dry and the floats and needle valves aren't letting any fuel into the carb, I think if the accelerator pump is pumping gas then the bowl of the carb is full and the floats are likely fine, and more likely those plugged passage ways

 

[NHGuy]

The fact that you got fuel when cranking it a very positive thing, but...when you emptied the tank I hope you went to town getting it hospital clean on the inside.
Otherwise you chance sucking more crap into the filters and the carb.
Once you trust the tank, dump the fuel from the fuel/water separator into a jar and let it settle out. Check the fuel for contaminants. Replace it again, they can't be reused cause dirt gets on the engine side once they are removed. Go over the carb again. You gotta watch out for the sequence or you end up redoing things.
Stinks but that's what you are dealing with. Been there, got the t shirt.

 

[PS94]

How much fuel are you getting? Is there a rubber line anywhere? Sounds like she may be running out of fuel supplied to the carb...I'd make sure she can fill a 2 liter soda bottle in a hurry before pulling the carb apart again...

. ""When I had my son pump the throttle lever, I could hear the accelerator pump moving up and down but could not see any gas squirting. Shouldn't gas squirt into the throat of the carb when the throttle is pumped?""

Yes. this leads me to believe that you are starving for an adequate supply of gas TO the carb...check filters, deteriorated rubber lines, weak pump, etc...

 

[bigbob_FTW]

If I'm not mistaken there is a filter in the pump. Check it and clean if needed.

 

[sweebs]

on emptying the gas tank I did not do anything beyond pressurizing the tank by plugging vent and blowing compressed air into fuel filler hole. Gunk in the tank does concern me and I'm hoping the fuel filter before the fuel pump does its thing and the filter screen in the carb where the fuel line attaches catches fines if need be as both those are easy to inspect and change if need be. However, if there is some effective way to clean the tank via the fuel level sender hole which is maybe 2" in diameter, I'd love to hear tips and tricks and I'll just empty out the 27 gal of fresh gas and put in my truck and start cleaning away.

the fuel pump obviously works but I will look into testing it's output to verify if working adequately.

*** I just went out and started her up (which it now consistently will do when cold) ran fine at 1500 rpm, then when I idled down it did the now expected stumble and die. Try to restart and no go. Put a heavy wrench on top of carb to close choke plate and she fired up again.

Since it won't restart when choke is open and engine had just been running for 3 or 4 minutes but will start if I manually close choke, does this narrow down what is going wrong for any of you gurus?

Thanks again everyone for your advice and input, I feel I'm so close to finally getting this new to me boat on the water and I just need to find that final missing piece of the puzzle!

 

[sweebs]

oh yeah, this boat does not have a water/fuel separating filter, just a black canister with the rubber hose from the gas tank clamped to the intake side and the metal fuel line to the fuel pump on the output side

guess the link doesn't work? I dunno

here's pictures http://s448.photobucket.com/?action=undefined

 

[NHGuy]

Well if it only runs with the choke held closed you probably have an air leak somewhere. Tighten any loose intake manifold bolts, and carburetor hold down bolts. Let us know if there were any loose.
Your photobucket link was a dud. But keep removing those inline fuel filters and check for sludge. If it appears you might have to do the tank clean up. But in the meantime you can run it off a portable tank that has clean fuel. BTW use regular, premium does no additional good.

 

[sweebs]

well I can easily recheck intake bolts but I just installed that recently and carefully torqued bolts down per spec and used a brand new Fel Pro marine gasket set for the heads, intake and exhaust manifolds (as well as all new gaskets in the carb, water circulating pump and everywhere else,, I just can't imagine where there could be a vacuum leak (plus even used Permatex aviation sealant).. troubleshooting continues I guess!

 

[PeterB26]

I had something similar with my carbureted engine. It turned out to be crud in the inner passages of the carb. I opened it up and cleaned it out perhaps a dozen times and it would work for awhile, but in fact I never really got the offending crud out. So even though I thought I had "fixed" it sooner or later the crud would clog the passage again and I'd get back to the starts cold, but when warms up will stall at idle. Mine was a 2 barrel Mercarb and the crud was inside one of the emulsion tubes. It was probably that way from the factory, a bit of flash or chip of casting or something.

Here was my soultion and I should have done it much sooner!

http://marinecarburetor.com/?gclid=CJKjyMHLnMcCFYOPHwod9-EMVA

Great service from tehse guys and I got precisely the carb I needed. It seemed expensive at first, but I haven't had a problem since.

Peter

 

[sweebs]

thanks PeterB, so are you saying you bought a new carb altogether? Pretty much wish I did that before spending the time and money on the rebuild kit and new electric choke/thermostat, but may very well be what I am needing to do at this point, because I don't see how I could have been any more thorough in the cleaning of the carb, but you may be saying well, no wonder you're having problems - if I could get a picture to post, you'd see just how much crud was in the carb before rebuilding and cleaning - tons of rust "dust" or powder, tons of rust in general and the unavailable power piston's spring was in pieces and I stretched out what was left to attemp to restore some 'power' to the remains of the spring.

 

[rebars1]

Is there a on-off solenoid (valve) between the fuel tank and the engine that may not be opening? That happened to me once when I could not get the engine to run. When I hooked up a portable tank, it started right up and ran. Turned out that a wire had come disconnected from one of the fuel line solinoids, so gas was not being delivered to the engine. Maybe try connecting a portable tank (like for an outboard motor) at the point where your fuel line attaches to the engine/fuel pump and see if works.

 

[zealer]

sweebs, you need to go back and check your work. Just saying you followed the instructions perfectly isn't sufficient. Mistakes are very easy to make and difficult to catch - it is the nature of the beast. It has happened to me (and many others) where I think I have done something perfectly, yet I don't get the result I want. When I go back and check, the usual cause is I made a mistake somewhere along the line. I end up doing the job twice. It sucks, but it happens. Last boat I had, I had to pull the motor a second time because I didn't tighten the distributor clamp enough. Distributor popped off cam gear, no oil pressure, engine wouldn't run. No room to do distributor in the boat, had to pull. Small mistake, big problem!

You have a fuel problem, you need to thoroughly check everything. Frankly, this sounds like a typical carb problem. Runs at higher RPM, but won't idle. Of course, I can only go off the information you have posted, but based on what you have posted, I suspect the carb - like others have said.

 

[sweebs]

yeah Zealer, you're probably right, though just hearing the engine fire was a huge relief, having it been seized, me tearing it down to a short block (never done before) and reassembling the entire engine back from the heads/push rods/rockers, to the intake manifold, to all the accessories, installing new starter, cap, rotor,ignition sensor, coil, plugs and wires, and all the accessories plus rebuilding the carb - except cap, rotor and plugs/wires - all stuff I've never done before, I'm totally pleased it runs at all. I've already given up hope of getting this thing out on the water, why not tear apart the carb for the 3rd time and do it all over again?!

 

[sweebs]

newest clues - cold engine starts right up no problem, running at around 2000 rpm for couple minutes, engine speed picks up on its own, I throttle back down to around 1500 rpm via the shifter/throttle handle, runs like this another couple minutes, engine speed picks up again a few hundred rpm, I again throttle down to around 1500, engine runs another couple minutes then noticeably slows down to under 1000 rpm, then slower still, I can tell what's coming next, she's about to die, so I gently attempt to throttle up a bit, as soon as I do I hear the whooshing of air with the simultaneous stumbling like it's going to stall engine, which stops if I stop pushing throttle up, I did this couple times with same results to where I just laid off throttle and she died. I was able to immediately restart engine with 3/4 throttle but backfired a little and died. Did this again, and another backfire and when tried to lower rpms she died..

started up again an hour later, got her to idle down at 600 rpm, no backfiring, exhaust smelled rich, played with idle mixture adj screw, played with timing (still not timed with light yet) and did die and wouldn't immediately restart.

tomorrow im going to see about renting a timing light, dial in the timing and try to dial in idle mixture, and just see what happens

 

[sweebs]

apparently timing lights are something none of the auto parts stores - that do loan tools - actually loan out. So the timing is just going to be what it is for now. I just had it running the longest yet - 10 whole minutes -with the throttle in the neutral position, was running about 1100 rpm, I fiddled with idle mixture tried closing a bit to slow idle speed but it just made it stumble, after 10 minutes I was going to rev it up a bit to play with it and it immediately died and wouldn't restart... So frustrating it seems like there's a slightly different set of occurrences every time I run it

 

[Rick Stephens]

Doesn't take much for the timing to totally screw up your idle if it is off.

Same for carberation, especially combined with guessing the timing. When the carb is plugged somewhere, it will probably run mid throttle, where it is fed a lot of fuel and air through the largest and easiest to clean ports/main jets. At idle the smallest ports are what it's running off of and small changes make large difference.

At some point, if you want this thing to run, you are going to have to set things by the book. You might check local garage sales, old but useable timing lights are a common item. Amazon carries them from $15 through hundreds with very serviceable models in the $30-40 range.

I'm impressed with all the work you've done without any past history of engine work. Pulling apart a V6 is a big undertaking. Bravo and hang in there. You'll get this running perfect yet.

Rick

 

[sweebs]

thanks Rick,,, update for today is ran it in the driveway seemed better than ever, changed gear lube in outdrive, took to river and started right up,, idled fine while i parked the truck and trailer,, went into and out of gear ok, BUT,, I could only get her to move along basically at idle speed, whenever I attempted to throttle up, slowly, quickly whatever, it would die. Tried numerous times and always would die, at least she started back up though. If I pop out handle to lock out drive/remain in neutral, and then gas it, it will either die (like it did in gear) or if I do it carefully, and get past the initial moment when it stumbles, then I can rev it up no problem. pulled the kids on a tube at idle speed lol, for an hour until finally it died and didn't want to start back up. so put on trailer and called it a partial success and at least have more diagnostic clues to go on from here.. Oh, I do have some engine work history, about 27 years ago when I was a soph in HS I rebuilt a single cylinder briggs and stratton in small engine shop class lol