I have a '77 OMC Stern Drive with the Ford 302 190HP.

It has a 2BBL Holey that I rebuilt..after the carb rebuild it ran great...took her out 3 more times...no problems...

Well...the 4th time after the carb rebuild she ran great most of the day...then it started struggling to get above 2500 RPM...like the mixture in the carb was too rich...or it wasn;t getting enough fuel.

I verified the ignition timing (was converted to Pertronix Electronic ignition along with the carb rebuild). Puled the plugs...every cylinder looks to be firing. She has a new set of wires.

The motor will run great...but take her above 2500...and then she starts to stumble..its just wierd.

I checked the intake in the gas tank and it was not blocked.


Half tempted to replace the entire fuel line...then rip the carb appart again.

Someone said it may be a problenm with the new Ethanol Gasolines??? Said it was bad for carburated engines? Of course, I don't think this is the issue...

This is really starting to stump me.

Anyone got any suggestions?

It sounds like RPM limiting, but the engine is a bit old for that.

Something to check out, in case your fuel supply theory does not pin point anything.

Changed the fuel filter and water separator?

How about the fuel pump?

Bad ignition coil. When it happened to me, it started at WOT and went downhill from there untill it would just barely make 2,000RPM.

Will it run OK right away then get worse as it heats up? Another certain sign.


Cold mine woudl run fine, slam her wide open and wait 15 secconds or so, fall on her face till RPM came down.

Ignition coil....that would make sense...but it never reaches WOT. Maybe something to think about though.

I am going to replace the fuel line as it is over 30 years old...a few fittings leak a few drops of fuel..so I am going to go over the threads with teflon tape, retighten them and double clamp them.

I remembered that after I took out the fuel pickup tube in the tank and reinstalled it...the problem seem to have worsened a bit..the fitting leaked a few drops of gas too...

My theory is this:

If you suck soda through a straw with a pin hole in it, you get air bubbles and not very much soda in your mouth....

The fuel pump SUCKS the fuel out of the tank...so if thier is a small leak, the pump could be sucking air and fuel at WOT.

I don't think it is the fuel pump, as the diagprahm on a mechanical pump generally breaks when it goes bad...and fuel leaks on the ground (in the case of a car) or in the little glass thingamabob (in the case of a boat). Now if it was electric pump, I would hook up a fuel pressure gauge and have at it.....

We will see...I am taking her out on the resevoir tommorow morning...will replace the fuel hose, etc tonight in the garage.

Yup...that was changed at the beginning of the season (and checked again after this problem began)

Good Good...I was just thinking/starting at simple and cheap.

I would go with the coil theory - I've had one go bad and the first thing that happens is the engine runs bad at higher RPM, then it starts running worse and worse, until it won't run at all.

Beyond that it sounds like something went wrong in the carb - power jet clogged or something like that.

If your fuel line is 30 years old it could be collapsing under the pull from the pump and pinching it off. And line that old is a fire hazard big time! I suggest replaceing all the line from the sender to the carb.

you could run it on a portable outboard tank to see if the problem goes away, but if that old line is rotting on the inside you likely have bits of rubber in your jets and will need to clean the carb again.

I may just go down to the auto parts store and buy an epoxy coil...

The fuel line just got replaced...will see how she runs tommorrow morning.

Phill, while it may not be your problem, your leaking fuel lines scare the HELL out of me! There should not be ANY fuel leaks in a boat. And teflon tape is not a leak preventor and has no place on fuel lines/fittings. Please address this dangerous situation before you do anything else, okay?

Then I'll ask, is the bottom of the boat particulary dirty?

Another vote for the coil. Could be a fuel problem too, and as Billy said fix those leaks for sure, but I think the coil is your running problem.

I wouldn't look at an ignition problem based on "Pulled the plugs...every cylinder looks to be firing"...

A bad coil (or most any other ignition problem), will 'simulate' a rich condition, resulting in some wet and/or sooty spark plugs. Since If it's not firing but the plugs are reasonably dry and clean, it just about HAS to be running out of gas, lean condition...

Well...

Fuel line is replaced...

Spark coil has been replaced...

Fired her up...and gas was leaking out of the top of the carb...:X

Their is a little circular depression near the fuel inlet on the top front of the carb...it has what looks like a steel press fitting...that depression is filling up with gas...I could see it bubling out...never witnessed that before.


Rushed to the auto parts store (I figured I would take a standard 2bbl carb and marinize it myself by replacing the bowl vent with the curved one from the original Holley). They no longer stock carbs (well...OK...this aint 20 years ago).

So, I bought some JB weld, cleaned up the spot with the little pin hole leak, and am waiting for it to cure.

I am half tempted to buy some steel fuel line, a high pressure electric fuel pump, go over to the junk yard, find an old mid 1980's Crown Vic and rip the CFI injection unit off the motor... Only problem is, I would have to install then computer system that goes with it...and all the senors...probably have to install the HEI distributor from that era too... Damned shame it would be so much work, because that is a sweet little CFI setup...one of the better products that Ford put out in the mid 1980's. Yeah...I know..the parts wouldn't be "marine" either.

Bottom line, the bubble gum and bailing wire may be good for a little while, but I think I am going to have to pony up for a new carb

The bottom of the boat is farly clean...I only run it in fresh water (the only kind we have in Idaho) and the boat is never in the water overnight.

The fuel line leaks have been taken care of...that is a particularly dangerous situation; I agree.

Good that you're fixing the fuel leaks.

I just wanted to make sure you didn't have a "fouled" bottom that was causing a bunch of extra drag. Sounds like you are okay there.

And this will start a fight, but the Mercruiser EFI system on my boat is the EXACT SAME unit as on my 1990 Chevy Van. Still says "TBI" right on it. Also the distributor, distributor cap, and rotor are EXACTLY the same. Marine, schmarine!
If your repair doesn't hold, just get a marine carburetor and you'll not regret it.

Before you spend $500 for all that injection stuff, you might consider picking up one of these:



($130 brand new from Summit or cheaper on ebay)

and one of these for the top of it:



($336 from Summit, and it IS a marine carb)

You'll only have broken out HALF a thousand, and yer done with carb troubles...

FR, is that a Ford intake manifold pictured and priced?

it is! Summit brand, but probably made by Edlebrock...

Those Edelbrock carbs work great. Pretty much a direct replacement for the Carter AFB. In fact they are so similar I think Carter may be making them for Edelbrock.

I put one on an a Buick Vista Cruiser,(the coolest of the long roofs), a few years back and it was nearly perfectly tuned right out of the box. Five minutes later it was purring like a kitten. As I recall the Carter version was a bit cheaper. Don't know if it was marinized, or what marinizing would be on a carb.

Took her out today...
Same problem...get at about 2000 just barely on plain...advance the throttle and WAaarrrRRRrrrRRrrrrrrRRRR

I am going to call Holley on Monday and see where I can get a brand new carb of the same model.

I put her in neutral (in the water) and was able to get up to over 4,000 RPM. So the problem seems to be only under load. I think their is a boost valve?? (little screw thingy with a ruber diaphragm) in the carb that may have gone bad... (mechanic friend of mine thinks this may be the problem

Now, I put some Seafoam in the gas, and I was able to slowly bring her up to 3K, but that was about it...Something has to be plugged up in the carb.

That Edlebrock carb solution looks good...a new Holley carb would probably run me 500 bucks. Have to check the height on the intake manifold/carb and make sure it fits...

Holley DOES make a TBI kit that will fit an older 302.

Tempting...very tempting...I would never have another carb problem ever...Hmmmm...

http://store.summitracing.com/partdetail.asp?part=HLY%2D700%2D21&view=32&N=700+150+4294925061+4294907843&appfilter=1#Application

Forget that...I would have way too much money into it...needs a new 4V intake manifold.

The Eddleborock is a 4V Carb...I only want a 2V as I don't want to strain the old motor/outdrive.

I think I am going to go with a 500CFM Holley 2300 2V for $375. http://store.summitracing.com/partdetail.asp?part=HLY%2D0%2D80402%2D1&view=1&N=700+150+306083+

Hope my original intake manifold fits it.

If your current carb is a 2 barrel then that's the way to go, although it sounds like the Edelbrock 4 barrel and manifold are about the same price as the holley.

You should take the model number off the carb to make sure you get the direct replacement. That way the linkage will be on the same side and everything will fit. Try http://dougrussell.com/ They should have what you need.

Nevermind, I just looked and while they have carbs it isn't user freindly to look them up. You could give them a call and they may be able to help.

That 2bbl should work fine, might even be a direct replacment or at least it 'should fit' since you already have a Holley. Most Ford 2bbls are Autolite, and I'm sure Holley made their marine carb in '77 to fit Ford's existing manifold...

Well...

Replaced the carb..

STILL the same problem

I guess it is the fuel pump or the distributor.

I am going to have replaced half the boat by the time this is fixed

Have you checked compression?

Don't throw anything else at him, Hotbyte. He'll wanna change his compression now!


j/k phill. Good luck.