I posted up a topic a while back about getting maybe to much fuel during shutdown, did as suggested never really "solved" the problem though.

Here is where I'm at now

For the ones who don't remember when i switch the key to off, the engine stays running for a good 6 seconds or so. Before it would shut down immediately ( last season) i did fish the boat every now during off season and then and that's when this problem started. After it dies and i wait say a minute to try starting again it backfires a little bit and sometimes it will crank after turning a few turns. I also noticed the carb would backfire or spit out fuel while cranking it but not very often.

i took my intake filter off and placed my hand over the intake to kill the engine that way, when i do, it starts a little better.

I'm assuming when using the key, fuel is continuing to flow being the cam is moving still but the spark plugs are no longer firing which is leading to flooding and causing the back fire when starting to soon after turning it off.

I did notice two things when taking everything apart today. The cap that goes over the overflow tube coming from the fuel bowl was completely deteriorated, any backyard fixes on this one? and the rod that runs through the carb controlling the choke plate? would leak fuel when i would shut the engine off by covering the intake with my hand.

I'm thinking maybe something is happening with the fuel pump?

My motor is a 2005 gator tail so she has seen some better days now.

any other suggestions?

Leak down test results
test was done on a cold engine and with a cheap Harbor Freight tester, then did another test with a high psi set-up
Port side was first: TDC on the compression stroke, air leaking from carb, nothing out of exhaust, then pulled the dipstick....more air. Leak down %25

Starboard side: TDC on the compression stroke, air leaking from carb, nothing out of exhaust, pulled dipstick again.....more air again. Leak down %22

pulled the low psi gauge off, put on a high psi gauge, redid test at 90 psi, was loosing about 15% both sides same leakage spots.

obviously im having some valve issues. My bigger concern is the air leaking out my dip stick tube (didnt even think to check the breather on the valve cover ) im aware of what it could be like the rings bad, pistons shot etc etc. It just seemed weird both sides were almost exactly the same.

So what do yall think about the results? Heads will be coming off either way this week when i get time, just curious for some opinions. thanks

what is ur idle rpm set at. ? valve lash - cam timing - flywheel key. have u done a comp test. and a leakdown. ? do a general r/x of ur engine.

idle oow not engaged is at 1700-1800, valves are .004 intake and exhaust, cam timing - flywheel key (best way to check that please?) ill do a compression test tomorrow, and a leakdown will be next, i could almost bet i have leaky valves though being its 05 and to my knowledge has had no headwork, but would that cause this problem? thanks for the reply

run ur idle down to 1000 rpm. reset ur idle air mixture. open up ur lash a hair. post up results.

will do

before i go jacking around with the idle adjustment screws just want to make sure this is the proper procedure for the 35 vanguard. Also im assuming the idle mixture screw would be the one on the starboard side of engine.

Adjusting The Idle Speed And Mixture

On some float-type carburetors, you can adjust the air-fuel mixture and engine speed at idle. Check for an idle speed screw designed to keep the throttle plate from closing completely, and an idle mixture screw that limits the flow of fuel at idle. If your carburetor contains these screws, proceed below.

With the engine off, remove the air filter and air cartridge.

Locate the idle mixture screw and turn it clockwise until the needle lightly touches the seat. Then, turn the screw counterclockwise 1-1/2 turns.

If your carburetor has a main jet adjustment screw at the base of the float bowl, turn the screw clockwise until you feel it just touch the seat inside the emulsion tube. Then, turn the screw counterclockwise 1 to 1-1/2 turns. Replace the air cleaner assembly and start the engine for final carburetor adjustments.

Run the engine for five minutes at half throttle to bring it to its operating temperature. Then, turn the idle mixture screw slowly clockwise until the engine begins to slow. Turn the screw in the opposite direction until the engine again begins to slow (image A). Finally, turn the screw back to the midpoint.

Using a tachometer to gauge engine speed (image B), set the idle speed screw to bring the engine to 1750 RPM for aluminum-cylinder engine or 1200 RPM for engine with a cast-iron cylinder sleeve.

With the engine running at idle (image D), hold the throttle lever against the idle speed screw to bring the engine speed to "true idle." Then, repeat the idle mixture screw adjustments from Step 4 to fine-tune the mixture (image C).


Adjusting The High Speed Mixture
Some older carburetors contain a high speed mixture screw, near the throttle plate and opposite the idle speed screw. Under load, the high speed circuit increases air flow through the throat. Setting the high speed mixture involves running the engine until it is warm, stopping it to adjust the high speed mixture and then restarting for final adjustments.

Run the engine for five minutes at half throttle to bring it to its operating temperature. Then, stop the engine.

Locate the high speed mixture screw and turn it clockwise until the needle just touches the seat. Then turn the screw counterclockwise 1-1/4 to 1-1/2 turns.

Restart the engine and set the throttle position to HIGH or FAST (image E). Turn the high speed or main jet screw clockwise until the engine begins to slow. Then, turn the screw the other way until the engine begins to slow. Turn the screw back to the midpoint (image F).

Once adjusted, check engine acceleration by moving the throttle from idle to fast. The engine should accelerate smoothly. If necessary, readjust mixture screws.

ok, i had time to do just the compression test and opened my lash to .005.

compression dropped since last time: port side = 130 and starboard = 135 (thats with a warm engine)

i dont know if its me being paranoid or what but i also here a little air puff out the intake when i shut it down

all symptoms are still here, thinking of doing a leak down test tomorrow and probably be pulling the heads i bet

did u set ur oow rpms down from ur previous 1700 to 1000 rpms. ?

not yet, was going to do that today, i had problems getting those black caps off the mixture screws? dont they just pop off?

i've seen people being to agressive break the screws before. i've always took a exacto knife and heeted up the blade and cut slits and then they can be removed quite easy.

ok, so im guessing you really dont need to put them back on?

damn standards

ok, nagon, dont kill me yet but i didnt put the idle to 1k yet or adjusted the mixture screws, that will be next, i just happened to think about maybe checking the timing and at TDC on the compression stroke this is what i have.....should this be ok?



while i had it apart i went to check my key, is this the one im looking for or a different one?




also the cap that goes on the carb overflow is barely holding together, simple hardware store replacement or what?

RN is having you start simple- adjust the idle it is WAY too high (~1100 is standard). Looks like you are pulling the whole thing apart. Just replace that rubber cap with anything that will seal it and set your idle appropriately.

at 1800 rpms ur transitioning from ur idle curcuit to ur pilot curcuit. causing a fair amount of fuel going into engine. at shut down ur chambers and exhaust have excessive fuel build up causing ur start up back fire. not a lack of fuel i don't think. also at 1800 rpms u will have a longer shut down time than at the recommended 1000 rpms. and at 1800 rpms u can't set ur idle mixture. i don't see ur carb running out of fuel in that amount of time. set ur idle down and adjust ur air and post back up. thats where you need to start.

yes sir, first thing in the morning ill do that. But funny part about all this is that the motor has always had high rpms. I didnt know any better when i bought this motor and i was lied to more than once on details about this motor. But we all learn our lessons and what goes around comes around..... jack..ass.

anywho, being that it always ran rpms like that on idle, this symtom poped up running it a couple months ago. but ill head out tomorrow and get her adjusted properly, and get back to ya. thanks for all the help.

ok, so was able to get the idle down and steady at 1200, adjusted the mixture screws as i listened to engine. After several minutes i noticed i dropped a cylinder, found it to be the starboard side. I have had problems before in the past with this side and put some electrical tape on it, started working fine, said i would order new armatures, but obviously never did. pulled the boot off and the metal snap connector was rusted but was still able to arc over, note though, not a very strong arc to ground. cleaned it up a little bit, and made a lil bit snugger fit over the plug. Cranked her back up with no problem was running fine. noticed the rpms were higher 1600??? started to work on that and of course a couple minutes late i drop the starboard cylinder again.

So seeing the lower idle fixed my stopping and starting problems, two more arouse

One i guess the linkages are playing hell with me, because if i have it idling at say 1200 sometimes when i crank her back up i get 1600 or so at idle even if i push back on throttle and let it sit there. But i also think this has something to do with armature problem

Second problem, the armature. I'm no engineer or master mechanic but im guessing the coil is getting to hot after running a few seconds and i loose full spark? or is there is a bigger problem?

If the clip is not snug on the spark plug because its rusted out you will need to solve that. I have seen some aftermarket clips installed on a coil wire with the original clip trashed- I think BoatDr was the source.

Also check for air leaks, a lean condition will increase RPM and leaking air will give you erratic idle. If you have been re-using the gaskets you may have leaks.

If you want to isolate the wiring harness (the diodes can go bad) disconnect the ground wires from both coils and see how it runs. NOTE you will have to choke it or remove the plug wires to kill the motor as the key and kill switch are disabled.

don't know were u taped ur coil wire at. but that sounds like were ur problem is at. some times u can slide some heet shrink over bad area and retape and buy some time. and a bad plug clip can cause problems. u can get replacements. might be time for a new one. coil that is. u can also confirm a bad spark by hooking up a spark thru spark tester. ur surging idle could be as dead bird says. but also ck ur throttle cable for easy movement thru the plastic sleeve. and make sure ur carb linkage is not binding and that ur return spring is good. i use propane thru a torch head to ck for intake and carb leaks. just don't lite the torch.

i went ahead and just ordered new ones because i found a crack at the armature side where it connects to it anyways. I also had it taped originally from the spark plug boot to about an inch inside the shroud.

i will test my gaskets for leaks again once i get the new diode in and can hopefully keep the cylinder this time around.

I probably need to replace the whole throttle and handle because it is starting to crack anyways, but i will check to see how it is moving along by the clip thing. Carb linkage is good, i actually just had to install a new one due to the other one breaking at the shroud. and this return spring.....are you speaking for the throttle? if so which one is it? is it the one that the linkage is run through?

and sometimes i wonder if it would be better to just lite it haha, thats horrible this engine has been good to me considering the neglect it has been put through from the previous owner.

and this return spring your talking about, is it this one? because i dont see one on my engine



or this small one on the other linkage

new coil installed on starboard side, played hell getting my idle to stay right along with my governor. noticed my other cylinder (port side) was not firing right when i touched the exhaust on that side. pulled the mixture screw blew air down and that seemed to keep it running right after readjusting the screw again. As it stands right now im idling "ok" at 1250. turns off find and starts good again. Guess ill go run her in the water this afternoon and make any final adjustments for now.

But it doesnt end here, i believe i need to probably replace some gaskets and do some tlc work. And with my springs and linkages, if you back out the screw for the governor does that lower or raise the WOT rpms?

Unscrew = lower, screw = higher.

thought so, thanks