Help needed w/ 8hp / 4 stroke

[TownsendsFJR1300]

If you do as I did, flip the carb over, float bowl off, float and needle in, it'll be in the closed position.

I use an extra fuel tank (small from an old lawn mower for diagnostic purposes).

Hook up fuel to the line to the carb.

If you lift the float (open) fuel will flow obviously. If in the closed position, it still leaks fuel, the needle is not seating fully (like my above Honda mower) and will flood.

Wether the new needle has a rubber seat built into it or the carb itself does, I don't know (one will). If a new needle passes that test, that part of the carb should be ok.. If its real sloppy in there, it likley won't seal well..

Very simple test


Please post what you come up with.

[Wharfcreek]

OK,

First, Rodbolt....thanks for responding. Glad to have some confirmation about that oil pressure light. I had 'guessed' that's what it was in the beginning......but certainly got thrown for a loop by bad advice from a Yamaha dealer!! But, glad to have it cleared up now.

Second, Chrissy....... If I DO buy a new carb, I'll certainly be happy to make a deal with you for the old one.

Finally, Scott...... spent perhaps another hour on the carb last night. I managed to get the main jet out....and as I suspected, the ''mixing" or 'emulsion' portion wasn't really badly contaminated or blocked. Perhaps a couple of the small holes....but overall, I think it would have cleared up OK if it ran for a while with some good fuel and perhaps some 'fuel system cleaner' additive...which I'm a HUGE believer in. Anyway.....I was unable to remove the low-speed jet (Idle jet).....and it actually 'cracked' under the pressure of the screw driver. By that, I mean that the 'tabs' where the screw driver blade fits into.....one of them snapped off.....so now there's no way short of drilling and using an extractor of some kind to remove that jet. And, that would likely bugger something else up beyond repair, so, that may become the decision maker as to whether this carb gets replaced or not. I will say that the idle passages all seem free...the idle jet is 'open'...and I can spray carb cleaner up into the jet and see it coming out both the idle port and the transfer port. So, while the small mixing holes in that jet may still be blocked......at least it's passing enough fuel that the engine should 'idle'. And, with the main jet free and clear.....I'm back to the condition of the float valve.

As to that, I spent some time polishing the four side rails of the float needle itself.....and hopefully smoothed those out enough that they won't hang up in the needle bore. I also 'inspected' that bore area again.....and after a really hard look under the magnifying glass with some good light.....I'm not so sure but what that surface might be OK. I DO see what looks to be a small fracture in the side of the viton tip of the needle...which may distort the shape of the needle tip and thus may affect it's ability to seal properly. But, I worked that chamber some, assured the entry port within the 'seat' itself was open and clear.....and then did the 'blow' test before re-assembly. With the carb inverted, I can't blow any air into the fuel inlet port. With it upside down, I can slowly blow into the float chamber. So, maybe it's working.....maybe not. But, it's re-assembled...and in just a bit I'm going to re-install it and see what happens next.

I'll tell ya all this: I can now get this carb 'on' and 'off' in probably under 60 seconds!! In perhaps another 60 seconds I can have the bowl off...... Sure would be great if this time was the 'charm'....but if not......'R&R' is certainly no problem!!

Thanks to all for the help, comments, and interest! I'll post again after I give this a try. I have an appointment at noon today with my Tax guy..... The Fed sent me a nice letter saying I owed another $2K in 2012 taxes!! Un-froggin-believeable!! So, guess we'll see if I can afford a new carb or not!

WC

[Wharfcreek]

OK.....final report! Looks like I've got it running properly! Briefly, as I'd indicated in the prior post, I'd spend some time last night reworking the carb again. In that process, I made a 'judgement' call.....and enlarged the small opening in the brass 'seat' section of the float Needle assembly. And, I also 'tweaked' the float just a bit......so as to raise the fuel level within the float bowl itself. Upon reinstalling the carb this am.......One pull and the engine not only started....but it purred like a kitten.....accelerated flawlessly, and clearly had a good deal of torque, as the twist of the throttle literally caused the boat to jump! I was delighted.....except for one thing: I had a steady flow of raw fuel leaking out the intake. Clearly.....while the carb needed fuel.....it was now getting too much fuel. So, I had two choices.....either go get the new needle valve and try to re-set things.....OR......try to drop that float that I'd raised up a bit...and see if by dropping it just bit I couldn't get the needle to seal yet still deliver enough fuel for the engine to stay running. At $35 for the needle, $8 in tolls to go get it, and nearly an hour's drive one way... I opted for the 'cheap' try first. Like I said, I'm down to a removal time of about 2 minutes........so....what the heck! Off came the carb....again.....and out came the Float .... again.....and I made a calibrated 'bend' in the level tab....re-assembled it......and ...... PERFECT!! Started on the first pull....again purred like the proverbial cat......revved beautifully..... and after about a 10 minute idle I made just a couple of 'adjustments...then shut it down to prepare for a 'water' test. The idle seemed a bit high.....so I dropped it some using the throttle position screw. I also tweaked the idle mixture screw....and noted that the futher out it came, the more RPM increased. I didn't back it off to the point of seeing the RPM drop....but if it's like many other carbs I've worked on in the past.....it's probably a bit 'lean'...as I think this mixture screw actually backs off and 'adds' fuel.....or, screws in and cuts fuel. So, if the air is constant by virtue of the throttle plate position, then backing off the screw and adding fuel and having the RPM increase is..to me.... a sign that it's a bit 'lean' at idle. I think this is pretty common as it meets w/ many of the Federal Emission demands.

Anyway.....until I get it under a load and see how it runs at idle while 'in gear' and pushing the boat, I guess I can't really give it a final blessing. But, if the performance I noted today was any indication of what might be yet to come....... I think I'm going to love this little motor! My first venture into the world of 4-cycle outboards.......and hopefully it will be a favorable experience. So far.......I'm liking the direction this is going.

Thanks again to all for the help............. Forums are really a wonderful invention of modern times. Just think; ...... 20 years ago, you'd have been on the phone or nosing around a book....and probably getting no-where fast!! Today, you post a question at bed time, and in the morning you awake to a world a glorious information!! It's a beautiful thing!!


Tom D.

[chrissy t]

Glad you found the problem and got it running. Now you can fine tune and enjoy.

[TownsendsFJR1300]

Excellent!

BTW, any adjuster screw past the thottle plate (before the engine) controls fuel and yes, the farther out, the richer on the bottom end.

And the float (adjustable) when the carb is upside down, in GENERAL, is best set roughly even with the carb BODY gasket surface.

There is a set # for setting the float height, which would be the correct way to set it but it sounds like your good.

Please post your final test run (and keep an eye on the color of your spark plug for color (A/F ratio's))

[TownsendsFJR1300]

Glad you found the problem and got it running. Now you can fine tune and enjoy.

Now you get to hunt down a throttle shaft...

Is your TS bent or just worn where it goes thru the carb body?

[Wharfcreek]

Chrissy......sorry I won't be selling the carb......but honestly, quite glad I didn't have to pop for the $350 for a new one.

Scott, good advice on the plug insulator color watch. I'll do that. Unlike a lot of 'lake' boats, I run a 'sea level', so air here is as dense as it gets...which simply adds to any 'lean' condition that might already be 'tuned in' to an engine from the factory. I've often wondered why so many manufacturers call those 'idle mixture' screws 'air' screws? The one on this carb is #16 in that fiche you sent me.......and called a "screw, air adjusting" in the nomenclature. Yet, moving it one way or another does nothing to 'adjust air'. So, why not call it an Idle Mixture Screw like they did in the 'old days'???? Maybe because they don't want you popping that plug out and 'enriching' the mixture as a function of Air Pollution Control..... Who knows. All I know is that it runs better with about a 1/4 to 1/2 a turn 'out' from it's original setting...which was barely 3/4 of a turn off the seat. So, at about 1 1/4 turns, its smooth and responsive OUT of the water. Hopefully it will be equally so IN the water.

I'll do a final post when I return from my 'trip' with this boat. Heading to Delaware later today, dragging the boat with me, and HOPING that I've fixed it. I'd hate to get out in the Indian River Inlet Bay and find myself stranded. At least I purchased a good set of oars.

Tom D.

[TownsendsFJR1300]

Most carbs nowadays have covers or doo dad's that prevent any adjustments or severly limits the adjustments. Most if not all require a special tool to adjust the screws as there is no slot to prevent the average Joe from adjusting it. I take a Dremel and put a slot in the head of the screw, its adjustable now!!

I get weedeaters/ chainsaws all the time that run crappy, won't idle down. fatten up the high speed needle some(maybe 1/4 turn?), a whole different engine...