new carb new issue

[newtoboat101]

hello, ihave 1988 thompson 240 HT ,mercruiser 305lx with alpha1 gen 1 drive thunderbolt IV ignition, i swapped out my old Q JET for edelbrock 1409 600cfm ,used the plate kit with fuel line to make swap everything went fairly easy maybe 2 hours total ,so took boat out went for 6 miles seems better then my old carb ,little hesitation off when i went up to 2000 rpms ,ran it about 2500 for 6miles ran ok ,seems like it was starving for fuel then slowed down, stopped ,put in nuetral ,idle for about 5-7 minutes , then just died, went to restart ,just cranked over but nothing ,not even a sputter,checked electrical connection ,did not see anything out of order,so i used my trolling motor to get back in close to shore ,then worked on it ,got it to fire up moved dissy a little to get to start,but was struggle to start, why would this happen ,did i have carb idle adjustment to rich ,or could be some sort of "vapor lock " or bad ignition coil ,cracked dizzy cap ,what the heck, before this did not have an issue like this,,did it start back up after cooling down ,temp ran about 180 at 2500 rpm and same at idle thank you for checking out my post

 

[Scott06]

What do spark plugs look like

is timing set to spec so you have good spark ?

does choke fully open

what do contents of fuel filter look like

 

[newtoboat101]

good questions
Did not inspect plugs,should have pulled at least one,but did not and wont be back to boat till weekend , kickin myself for not
i did set timing and adjusted idle fuel /air screws before i took it out and after i returned . then i started motor let idle /revved ,turned off let sit ,then started back up and repeated 4 times no issues just started right up
As far as the choke ,i set the choke when carb was put on ,the only thing as far as the choke, that has me scratching my head, is when i was near shore trying to get it running ,i noticed that the electric choke positive wire was bearly attached , but the flap was wide open,could that wire being not securely on have caused the flap to close ,but that still would not explain why it just cranked ,and really had no spark sound ,just engine cranking
Fuel looked good thru clear filter ,something to consider is i have 1 filter near gas tank then to water seperator to fuel pump to second filter ,are too many filters bad thing to have on fuel line,also fuel was fine with old carb,why did i change carb ,i had hard time with Qjet adjustment and no consistancy, and out of the hole bogging
maybe its not carb related, another thing that happened was when it would not start ,and i would go to start my gps /chartplotter /fish finder flickered ,which i never noticed before ,but never really had to crank engine for long ,normally starts right up

 

[Scott Danforth]

my guess is you have a fuel system issue. check at the tank and check the contents of the fuel filter (replace filter element)

 

[newtoboat101]

will do ,also going to put new dizzy cap and rotor ,ignition coil, just to be sure, so you do not think ,"vapor lock " type situation , fuel actually has some ethonal in it could that cause heating in carb issue ,i heard that some where

 

[Scott Danforth]

its not your coil. I wish I had $1 for every good coil changed. I would be a billionare

 

[newtoboat101]

ok ,i'll take your word for it ,will leave coil alone ,i did not think so either ,but ,i just start replacing stuff ,thats just me ,i have been thinking about what you said earlier about fuel ,how can i work thru thatif its the problem, stabilizers or add non ethanol fuel? have little under 1/2 tank,,boat in a slip,so draining tank is not really possible ,gonna replace my water seperator what do you think about ignition sensor replace or not an issue?

 

[newtoboat101]

also the fuel filters are brand new, water stabilizer is 1 year old

 

[newtoboat101]

fuel/water seperator

 

[Scott Danforth]

also the fuel filters are brand new, water stabilizer is 1 year old

WTF is water stabilizer

If you mean fuel stabilizer, it extends your fuel life up to 6 months. No more

Start with what ever is in your tank

 

[Scott Danforth]

what do you think about ignition sensor replace or not an issue?

Test first

Mindlessly swapping parts will cost you 10x doing a proper diagnostic test

 

[newtoboat101]

sorry,as my name says, new to boating, sometimes i miss type and had to correct, i think fuel/water seperator is correct ,i drained my tank down to less than 1/8 tank before this season ,and then filled up with fuel in june ,this year and added that ethanol stabilizer stuff,,can not remember brand name, ihave been running this boat out to same fishing spot every other weekend ,with it not having the issue of stalling ,then not firing back up, only thing that was changed was carburator,reason i got rid of Qjet was inconsistant and bogging

 

[newtoboat101]

i have something else to add ,may not mean anything for this problem ,but while i was timing and tuning engine and carb after i got back in , inoticed alot of gas /oil behind boat, would this be normal,never looked or noticed before ,so lets say i had the boat running for 20 minutes ,how much should there be normally ,and is this to much fuel/oil in the river, and could i be way to rich at idle

 

[kenny nunez]

Are you sure the choke is staying fully open? Your Idle mixture screws should be 1.5 turns from seated. If you have a 2 barrel Rodchester.

 

[flashback]

When this sort of thing happens to me I generally find the last thing I was messing with is usually the problem. Also 180 temp is a bit warm.

 

[Lou C]

If that’s fuel in the water it would seem that three possibilities exit:
Electric choke not staying open
Carb floats sticking or needle valve not holding
Fuel pump pressure too high
That’s way more than what you’d see from the idle mixture being too rich.

 

[newtoboat101]

edelbrock 1409 carb , yes choke is staying fully open, gonna add a fuel pressure gauge ,it was like someone just turned the key off ,no sputter,just idle to dead ,then wont start back up ,and to me it felt like no spark ,unplugged and plugged back in tb4 ignition module on exhaust ,but nothing, It wasn't til maybe 45 minutes later ,after sitting, That i got it started but that was a struggle ,pumping throttle while starting, then finally turned over,

 

[newtoboat101]

thanx lou c

 

[Lou C]

I’d check for spark when this happens next time. You just want to cover all the bases

 

[newtoboat101]

ok checked plugs ,plugs look fine ,as they were brand new ,prior to this carb issue, went to start engine ,engine started ,then died. looked down carb ,and fuel bowls were filled with fuel ,and continued to pour fuel into bowls,after it stopped took carb top off ,checked floats ,everything measured correctly put back together, pulled plugs ,they were soaked with fuel ,cleaned ,dried, and gapped and put back in,motor started and ran ,so what happened ,,,just float was stuck? not sure ,hope it doesn't happen again ,uncontrolled fuel filling up my fuel bowls ,also put fuel pressure gauge in fuel line ,pressure was 5.5 . question ? when i turn motor off new carb lets out a hiss kind of like air out of bike tire sound ,about 3 seconds long,,like vacuum pressure release ,is ths normal?