94 Cobalt 220 not starting

[512Cobalt]

Hey guys,

Sorry for the LONG introduction!

Hoping you can help me learn / diagnose about the issue with my 1994 Cobalt 220 5.7L Volvo Penta. It's my first boat and I've done a lot of work getting it ready for this summer, but my knowledge of boats only just began when I bought it last year. My experience is all with customizing cars and trucks, so anything boat specific is probably not obvious to me.

Since purchase I replaced:
-Engine (0.30 over long block w/Xtreme marine Comp Cams roller setup)
-Exhaust manifolds and risers and boots
-Impeller
-Ignition coil
-Ignition Switch w/Cobalt key
-Flooring
-Carpet
-Outdrive cylinder seals
-Steering Wheel
...probably more stuff I forgot about right now.

It ran great the first day I took my wife and daughter out and we had a blast, although the morning before that it shut off on me right after I fired it up and would not restart. I assumed I flooded the carb by backing off throttle too soon before it warned up when it started right up every time the next day.

But then this weekend I changed the oil Saturday and had no time to put it in the water that day. Then Sunday it wouldn't start again. cranks and cranks but doesn't fire up. So, Monday (Memorial Day) I brought the MSD coil from my '88 s10 Blazer street truck and nothing changed. That's when I pulled #1 spark plug and saw orange spark jumping from screwdriver to exhaust riser. Then I looked down the carburetor and didn't smell or see any fuel when I moved the throttle arm.

At this point I'm wondering what could prevent fuel from getting to carb, since it has a mechanical pump on the block and an Edelbrock carb. Gonna bring a new fuel/water separator with me when I go back out, and distributor cap and rotor if they have in stock at my local dealer.

Can the fuel / water seperator totally block fuel flow?

Do these boats have an electric fuel pump in addition to the mechanical one? in the tank?

Are there other fuel filters in the path between tank and carb that can be clogged?

Is there a 'kill switch' on these boats? Where would it be? (I've never seen one, but I haven't looked either)


Thanks!!!

[AsLan7]

Kill switch is near the throttle.

[Driller]

See if you can reset the ECU with this hack. It might not work, but it did on my boat once when it would crank but not fire.

Remove the safety lanyard with the switch off.
Turn the switch to run (don't start the engine)
Within 20 seconds push the button on the safety lanyard 5-10 times (you will get the double beep when it is reset)
Turn the key off, re-install the lanyard and then start the engine.

If it is not just some kind of glitch the code should reappear. If not you should be good to go.

I've done this on my boat and the fault never reappeared.

Just a suggestion, I'm not a boat mechanic, but I can't see what it would hurt. The code should reappear if it is something serious.

[Big Block Power]

Driller sounds like he has the good old carburetor. Ok. Be careful. Remove the spark arrestor spray brake cleaner or starting fluid down the carb, put the spark arrestor back on and try to start it. If it starts and dies you have a fuel prob. Just please don't blow the boat up. No you don't have a electric fuel pump in the tank. The water/fuel separator can get plugged and restrict fuel to the carb. Do you have fuel at the carb. Do the basics first.

[512Cobalt]

Thanks guys!

Yeah, it had an edelbrock carburetor on it when I bought it and still does. I will bring starting fluid next time because it does not seem to be getting any fuel in the carburetor.

Regarding the kill switch, I’ve never seen it or a lanyard. When I had the exterior refinished last year everything was disassembled and reassembled so it may be hanging behind the panel somewhere? But, would it be wrong to assume that would cut spark and not fuel?

[akorcovelos]

fuel, spark, air. You've already confirmed you have spark and air, I'd take BBs advice and see if it fires on ether, if it does you have carb issues. Put an inline fuel pressure gauge on line going into the carb and make sure you're getting 6-8psi at the carb, if not, pull the mechanical fuel pump off and check the push rod for damage or wear on the cam end.

[Big Block Power]

fuel, spark, air. You've already confirmed you have spark and air, I'd take BBs advice and see if it fires on ether, if it does you have carb issues. Put an inline fuel pressure gauge on line going into the carb and make sure you're getting 6-8psi at the carb, if not, pull the mechanical fuel pump off and check the push rod for damage or wear on the cam end.

Yep what he said.

[512Cobalt]

Hey guys, I have updates...and more questions, lol.

While I'm stuck at the office today the service team at my marina confirmed that it does start with starting fluid and runs for a few minutes. It is not getting fuel from the tank through the carburetor like it should. They also said my boat does not have a kill switch (which I assume would cut spark anyway, not fuel).

So, now I am in urgent need of determining why it isn't getting fuel from the full tank to the motor.

Can a "anti-siphoning" valve block the flow completely?

I still haven't been out there to try emptying/replacing the fuel/water separator

Is there anything else in the path that could obstruct flow?

Comp Cams spec sheet says you must use a brass tip on the fuel pump pushrod with that cam. Not sure if mine had this or not, and why it matters?


Also, the service department said they didn't want to do any more work on it because it is more than 20 yrs old and has aftermarket parts. But since all I am asking for is diagnostic of fuel flow from tank to carburetor I asked them if they would make an exception and complete this while I'm stuck at work during the week, so I can try to take my wife out on the boat as planned Friday evening. They were checking with the boss on the policy.

In case they don't, what should my troubleshooting steps be when I go out there next?

Example:
-Remove fuel line from carburetor and crank engine to see if fuel flows out (if yes, replace carb)
-if no, replace fuel water separator and try again
-if no, replace mechanical fuel pump with brass tip version and try again
-if no, remove sending unit from fuel tank and inspect (maybe clogged sock?)

...don't know what else, or if I'm missing something here, or where this "anti-siphoning" valve I heard about is???


Thank you!!!

[512Cobalt]

This just in from Comp Cams:

"The bronze tip pushrod keeps from damaging the fuel pump lobe on this type cam. If you run a regular steel one, it can wear the fuel pump lobe off."

New question:
What is the best way of converting to an electric fuel pump setup?

I've been wanting to know this longer term anyway because ultimately I will switch to a FAST EZ-EFI Marine system, but not before my wife gets to enjoy this summer on the boat first. I've converted fuel injected cars to carburetor before by using an inline fuel pressure regulator turned down to 6psi, but I used the factory return line although I know there are regulators that don't require return lines out there.

With an electric fuel pump setup is it necessary to have a secondary push pump in the tank?

Do they sell in-tank pumps for these?

I've seen the electric fuel pump setups for a couple hundred bucks that appear to replace the unit that currently holds my fuel water separator. Is that how you would do it? Is that all I would need?


Thanks again!!!!

[Driller]

Driller sounds like he has the good old carburetor. Ok. Be careful. Remove the spark arrestor spray brake cleaner or starting fluid down the carb, put the spark arrestor back on and try to start it. If it starts and dies you have a fuel prob. Just please don't blow the boat up. No you don't have a electric fuel pump in the tank. The water/fuel separator can get plugged and restrict fuel to the carb. Do you have fuel at the carb. Do the basics first.

[akorcovelos]

Unless you do a lot of cold weather boating, or change elevation a lot, EFI is not really an upgrade for a marine engine, especially if performance is your target. Most people ditch the EFI for carbs when building hot engines, much cheaper HP and easier to do in your driveway.

That said, you need to know fuel pressure at the carb to begine knowing what to do next. How long did you run it with the new cam? The warning from comp leads me to believe you may have damaged the cam lobe for the fuel pump if you ran it for any length of time. Hate to be a downer, but if you can't get to the boat to do diagnostics, and the marina won't touch it, I'd make alternate plans for Friday.

[512Cobalt]

Maybe EFI isn’t worth the trouble after all then.

I only ran it for a few hours, maybe 4. But since the cam lobe that drives the fuel pump might be flat now I’m looking at installing a universal Carter inline marine fuel pump which puts out 5-7psi between the fuel water separator and the carburetor, along with a Carter oil pressure switch.

Any advice on going this route?

I wonder if my local boat dealer will have flexible marine fuel line and marine grade electrical connectors in stock.

Yes, Friday is looking highly unlikely...but i might still try for Saturday.

[akorcovelos]

You’re going to want to put the inline pump as low as possible, and it’s going to need to be wired to KOEO power so it primes before you fire it.

You’ll want an adjustable FPR and inline pressure gauges on the feed at the carb and return after the carb. Dial in 7psi in and size the return to be 0psi, usually 3/8”.

How do you plan to handle the return line?

Make sure you either get fuel injection hose clamps or go with AN fittings, don’t use regular screw clamps.

[512Cobalt]

Thanks akorcovelos,

Great questions. The pump I ordered is a Carter inline that only outputs 5-7 psi for carburetors. I selected this so no regulator or return line is needed. I will put a gauge in the line from the pump to the carb as a quick way to avoid uncertainty in the future.

In terms of wiring, the oil pressure switch I ordered is supposed to receive power from the starter solenoid on it's third pole I believe so the fuel pumps while cranking even though oil pressure is below threshold.

Does anything here sound wrong?

Thanks!

[akorcovelos]

well running the pump without a return is technically okay, keep in mind dead heading the pump will cause the impeller to churn when at idle and can cause vapor lock issues, as well as shorten the life of the pump.

Other than that, make sure you meet the USCG and EPA regs on going with an electric inline pump (page 92): http://www.uscgboating.org/assets/1/Ass ... 002.01.pdf