1992 OMC 3.0 WOTdies after a few seconds

[horndog]

Last night was the first night out, and out in Lake Michigan.

I let it warm up at the dock as I get the boat ready.
I idle out into the lake from the marina, and give a bit of gas, it was a bit choppy so RPMs did not exceed 2000-2500.

I set lines for salmon fishing and idled around to get the correct speed of 1.9-2.1mph.

I did notice the engine went from idle 750rpms to 1000rpms at some moments, but just made a mental note.

Due note, that acceleration does not stutter and it is quite responsive.
Pulled lines at sunset, and lake laid down a bit, and decided to head in.

I hit the throttle and at WOT or close to it, it would run then sputter then die.
Starts right back up and try it again to see what the issue is, maybe it is a one off..

Tried it again, did it again, and died.

Didn't want to risk anything else, so just puttered in the last few miles to the harbor.

I checked the plugs and seem to be burning fine, rotor had some crud on it, but I would figure it would be hard starting as well.

Any one have any clue?

OMC bashing is not cool, it is what it is, and until my wife can say it is ok to buy a $50,000 boat then it is what it is

Thank you!

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Bump

 

[Idlespeedonly]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Hello neighbor. I used to live in Brookfield also. Have you checked the fuel filters?

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Hello neighbor. I used to live in Brookfield also. Have you checked the fuel filters?

I may replace them all

 

[HT32BSX115]

Re: 1992 OMC 3.0 WOTdies after a few seconds

OMC bashing is not cool, it is what it is, and until my wife can say it is ok to buy a $50,000 boat then it is what it is

Howdy,

Yeah, but it is sure is FUN!! Sort of like an ex smoker bashing smokers!!:laugh: But this problem is NOT unique or related to OMC ........


You're going to need to inspect your fuel system carefully from the tank to the carb.

This sounds like a fuel starving problem.

You have a fuel tank with a vent tube that can plug (causes a BIG vacuum in the tank that cannot be overcome by the fuel pump)

Fuel pickup screen -- (partially) plugged,

Anti-siphon check valve (partially) plugged/stuck

defective fuel pump, partially plugged fuel filter.

Fuel line from the pump or filter (prior to the pump) leaking/sucking air

And finally carburetor problems.


Regards,


Rick

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Ok... I drained the gas tank over the winter, was that wise and maybe caused any issues?

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

I found an issue, not sure how much of it is the cause...

The anti-siphon valve... hmm, completely corroded around he fitting and as I was removing the hose, the valve broke off!
It was so corroded it broke! It looked like the crud around the fitting actually was holding it together.

Now I want to change the 90 fitting and the anti-siphon valve.

The trick is how do I know which one I need? Amazing.
I am still replacing the fuel filters

 

[HCMQA]

Re: 1992 OMC 3.0 WOTdies after a few seconds

My 4.3 cobra did the exact same thing. Could not figure it out for a while. But turned out it was the carb. Rebuilt it and it now runs like a scalded cat.

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

carb was rebuilt last year by an "OMC mechanic" sometimes I wonder...

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

The next biggest challenge is getting the 90 degree elbow out of the plastic tank as it is completely corroded. Anyone have any tips?

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

I replaced the broken anti-siphon valve and no improvement. I let it warm up at about 1200 rpms, but as soon as I put it to idle, it dies.
I also replaced the water/fuel seperator and did not see any clogs with the pickup filter.

The carb was rebuilt last year by an Evinrude dealer..

 

[Speak]

Re: 1992 OMC 3.0 WOTdies after a few seconds

(Bad fuel??) try a different fuel tank. If your fuel system checks out ok then move onto spark. A weak coil can also give weird symptoms. Points?? Also make sure your choke is coming off as well

Cheers Stu

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

fuel is fresh and treated with sta-bil marine. I am thinking it may be the carb due to the idle, when it does, jumps up to about 1000rpms and slowly settles back down, but it seems to only stabilize once a bit of throttle is given. I am not sure if the mechanic who rebuilt the carb may of set the idle/air correctly.

 

[Artwerke]

Re: 1992 OMC 3.0 WOTdies after a few seconds

horndog, you may have had the carb rebuilt last year, but after the corroded elbow, you probably have crud everywhere downstream. you may have to replace fuel filters 2-3 times to get all the crud out & a bad filter originaly could have let crud into the fuel pump & carb. A good running engine that dies at full throttle is almost always fuel starvation. Art.

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Art,

I am going to replace the fuel/water separator today, and see how it runs and it seems there is no filter in the carb.
True, but the anti-siphon valve broke while gently removing the hose off of it. Part of the rebuild last year was $2800 spent on a draining and cleaning of the tank(bought the boat and ran like crap), machine cylinder head and replace head gasket, new prop, replace and repair upper gears in lower unit, change oil, rebuild carb, replace all filters, replace hoses to and from lower unit.. etc.

But having the boat for over a month, and that kind of money spent, I would hope they wouldn't cut corners, but it seems that it would

 

[Silvertip]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Seems there is little "diagnosing" going on here and you are finding that "shotgunning" a problem is not the way to approach a problem. If you don't have the tools or knowledge to do tune ups, carb adjustments, electrical checks, fuel pump pressure checks, then you need the services of a reputable shop. If you are capable and have the tools, check the fuel system (from the fuel pickup in the tank all the way through the carb) including a fuel pump pressure & volume check. A carb rebuild means nothing if it was done by someone who thinks he knew what he was doing but really doesn't. A full ignition system check and tune-up if necessary including timing may be in order since this was not mentioned as having been done. Since the issue seems to exist at idle as well as wot and surging is present, that points to fuel delivery and the carburetor and it's adjustments are the prime suspect.

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

Sure a methodological approach to troubleshooting should be followed and fuel delivery issue sounds more logical than an ignition related issue. A carb rebuild may not be necessary or it was not completed correctly in the first place. But, in the interim, filters should be checked, carb adjustments should be checked.

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

duplicate post

 

[horndog]

Re: 1992 OMC 3.0 WOTdies after a few seconds

update:

Replaced the spark plugs, water/fuel separator.

I noticed the electric choke was set to open really early, so I reset the choke to default, and also set the idle mixture to default.

The result:

Idle was a lot higher, around 1k, but it was stable and did not die.
I turned the idle down to the recommended rpms of 650-750 and still idled without quitting.

I revved it up to about 2500 rpms in gear and in neutral and it didn't sputter and want to die.

But, it did stick to about 1200 rpms and did not kick back down to idle right away, is this normal behavior?
Granted, this was all on muffs so it does not provide a true picture, but it is definitely an improvement.

Also, if needed, I did purchase a carb rebuild kit, so if that will help the kick-down issue, I may go that route, but seems a bit overkill