omc 5.8l stalling 2k rpm

[sw33ttooth]

i have a 91 four winns sundowner 225 i believe its the original 5.8l omc hours at about 412 bought boat and it had no issues for maybe 2 months. now every time i take it out it starts up no problems and idles out past the no wake zone once i start to accelerate slowly over 2 or 2 1/2 rpm stalls no bogging just a complete stall i cant even drop throttle to neutral to keep it running. i tried just dropping throttle full down then it stalls immediately.

i naturally thought it was the fuel filter so i replaced it and old filter looked good inside. i tried to take the inline filter at the carb off but there is a double nut and i cant get a wrench to hold the nut against the carb to turn the nut on the metal fuel line. scared to break it then be out money to not solve anything. i took the air cleaner off and fired the motor up that just made it backfire the second i did anything over idle. however if in neutral i can rev it up to 4k for a second and back down flawlessly.

i know a lot on engines and could rebuild the carb not sure if i can tune it properly but it should be easy i am just wondering if its a dirty carb or...... i read the manual before i went to the gas station it said it needs mid-grade so that is what i have been putting in it however i have read that certain vehicals run worse with premium or mid-grade{hope this isnt the case with 50+ gal. of gas}.

as is there is no point in takeing it on the lake when i cant even plane out let alone cruise or hammer it for a minuite of fun.

thanks for reading hopefuly some one can help me hate takeing stuff into shops last time they didnt even hook up my throttle linkage and charged me twice what the job was worth.

added info:
took one spark plug out lookd good like it was just put on a few days before i bought the boat.
winterized boat myself and i had the problem last fall so it wasnt my fault.
before the problem occured i could cruise 27-30 full down about 38-40, was doing 35+ for 20 minuites or so was about as hard as i was on it.
put 10 hours on it last year after i bought it the oil stayed up on dipstick and its clean of anything.

 

[wbc1957]

Re: omc 5.8l stalling 2k rpm

Either fuel pressure issue casued by pump or carb float adjustment, or you have ignition problems caused by dwell and timing problems. Check your fuel filters first, since this is the easy fix, then check dwell and timing. If you have points, now is the time to clean contacts or just replace. Lastly, check fuel pressure.

 

[cr2k]

Re: omc 5.8l stalling 2k rpm

Check your accelerator pump. Pull the flame arrestor and have someone pump the throttle (engine off) and see if you can see a fuel spray going down the carb throat. If not your carb probably needs a rebuild.

 

[Joshua Nichols]

Re: omc 5.8l stalling 2k rpm

You winterized or just drained the water from the block? Gotta water separator on it? Looks like a oil filter but fuel goes to it...Could have really bad gas... Water and such..

After it stalls.. Does it restart easy?

Backfire back though the carb or out the exhaust? BTW that's not a air cleaner.. It's not very dusty on the water, that's a spark arrestor.. Keeps backfires from the carb from causing a fire..
Have you checked the tank vent yet( plugged up will cause fuel starvation)? Sometimes you can check if that's the problem, by leaving the fuel cap loose or off and stuff will start running right..

You would think a instant stall and backfiring, it would be ignition and or timing ; but seems like every-time it's bad fuel or bad fuel delivery.. Anyhow good luck with it..

 

[sw33ttooth]

Re: omc 5.8l stalling 2k rpm

re: joshua nichols
i replaced the fuel filter last august after i had the problem.

i winterized it myself draind the water, pulled off the 1 inch hose going into the block, and put 2 gallons of full strength auto antifreeze then preceded to the lower unit to drain and refill the oil then i put some Stabil gas saver in the tank.

yes after it stalls it starts right up as if i shut it off myself.

i backfires through the carb if the spark arester is off, you can't hear it back fire with the spark arester on i dont know if thats part of how it works or not?

as for the tank vent every time i top the boat off fuel comes out of the side of the boat and i have to be standing there or pump wont shut off{not sure why}.

i dont get how it would be timing if its in neutral i can rev it up for a second with no problems{dont want to cause engine damage}.

i havn't done and oil change on it yet mainly because it needs to be pumped out[havn't bought the pump] oil presure is fine when i am running it as well.

re: cr2k
thanks for the help i was thinking it may be the accelerator pump wasn't sure how to test it i heard it has a high and low setting and some times it wont engage high. but i was thinking that it might bogg down instead of a quick stall.

 

[Joshua Nichols]

Re: omc 5.8l stalling 2k rpm

I think it has electronic ignition.. So lets assume every thing is good there(less for some strange reason the distributor is lose)..

Start troubleshooting the fuel... fuel pressure from the pump.. Fuel quality...did ya check the vent?(stuff likes to clog that up during the winter).. Line could be kinked.. Has a Holley carb on it? I suspect accelerator pump too, but would think you could stop the stall but pulling back on throttle.. Weird.. If ya never overhauled a carb.. I suggest you get someone to do it.. Holleys are kinda picky about float settings and stuff.. BTW the choke isn't stuck closed is it?

 

[SeanMcl]

Re: omc 5.8l stalling 2k rpm

Start troubleshooting the fuel... fuel pressure from the pump.. Fuel quality...did ya check the vent?(stuff likes to clog that up during the winter).. Line could be kinked..

Good advice here ^^

I had a very similar problem, and it turned out to be a clogged fuel pickup in the gas tank. One thing you can do to check when you are on the water is run it until it dies, turn the key off and remove the float bowl fuel level screw (hope I got that term right) to see if you have any fuel in the float bowl. If it's dry, you know you have a fuel feed issue or the float needle is sticking closed on the carb. When the float bowl goes dry, you will get a sometimes backfire as it goes lean, which is one of your symptoms as well.

Use this link, http://forums.iboats.com/showthread.php?t=283269, to troubleshoot your fuel system.

 

[gdombroski]

Re: omc 5.8l stalling 2k rpm

i replaced the fuel filter last august

First, I would replace the fuel/water seperator as your symtoms sound like water to me. That should be a yearly spring time chore anyway. I bet that fixes it. If that's not it next replace anti-siphon valve. Both cheap, after those I would go on to earlier advice.

 

[sw33ttooth]

Re: omc 5.8l stalling 2k rpm

re: joshua nichols

far as i know distributor is tight i checked all the plug wires before i went out this year makeing sure they were all tight.

when you say vent do you mean the hole on the side of the boat next to the gas fill cap? if so every time i top the tank off[monthly] gas comes out of that hole and i have to turn the gas pump off it doesn't shut off.

it does have the holley carb on it as far as i know choke isnt stuck i will check tomarrow my cousin can tune edlebrocks he said he wouldnt know where to start on a holley and surgested if i did it myself count how many turns out the needle is and then make sure the new one is that far out[sounds stupid to me if its not set right]

i am going to put a few bottles of heat into the gas tank tomarrow and hope if its water that it takes care of it.

i guess i should change the oil as well i dont know the last time it was done and i know i put about 25 hours on it last year the guy i bought it from told me to use 40 weight which is desiel oil would 15-40 work as well?

operaters manual says it has breakerless distributor with exteral coil, so thats solid-state? not that it matters only takes 5-10 minuites to change points any way.

 

[Joshua Nichols]

Re: omc 5.8l stalling 2k rpm

Sounds like the vent is all good.. Bench setting for the carb is 7/8 of a turn..

Adding junk to the tank... Likely won't fix it
Changing the oil... Won't fix it..

follow the manual.. That carb is cake to rebuild..
I would check your delivery to the carb first

 

[vi]

Re: omc 5.8l stalling 2k rpm

Ditto on the accelerator pump, easy to check and fix. Carb is super easy then you know its done. Go to Wally world get some spray carb cleaner or just get the soak and can from the auto parts store when you get the rebuild kit, Napa s got them, you just need the stamped numbers on the top of the carb by the throat, the number stamped on the carb not the little tin tag. 20 year old carb can't hurt.