Video: What The Heck is This?? - 1999 VOLVO 4.3 GL - 2 bbl Holley Carbureted, ETS ignition

[tampamatt502]

Anyone that can figure out why this engine is doing this (not accelerating past 3500RPM and surging / dropping RPM at top end) wins the title of Google Dr Diagnosis for the day- thanks in advance!

 

[Scott Danforth]

You have fuel system issues. Start diagnosing

 

[Bondo]

Anyone that can figure out why this engine is doing this (not accelerating past 3500RPM and surging / dropping RPM at top end) wins the title of Google Dr Diagnosis for the day- thanks in advance!

Ayuh,..... Welcome Aboard,..... Video don't work,.....

Yer symptoms say that you have a fuel delivery issue, somewhere between the tank, 'n carb, or the tank, or carb,.....

 

[jimmbo]

I would do Compression and Ignition Checks, on both Engines before spending time on the Fuel System. A dead Cylinder on one engine will hold back the other engine. Operator can try running with just one engine at a time, to help narrow it down to which engine it is

 

[tampamatt502]

Hey everyone, thanks for the welcome and comments so far. Here is a better video of it. -Brand new Holley 2BBL installed, new fuel pump, new filters.. are there two fuel pumps on these?

 

[tampamatt502]

I would do Compression and Ignition Checks, on both Engines before spending time on the Fuel System. A dead Cylinder on one engine will hold back the other engine. Operator can try running with just one engine at a time, to help narrow it down to which engine it is

Compression was 195 on all cylinders but one at 180- spec is 15% of top compression, so that's good. We timed it too.

 

[tampamatt502]

Compression was 195 on all cylinders but one at 180- spec is 15% of top compression, so that's good. We timed it too.

Also, it's the STBD engine- here's what has been done chasing this gremlin:

I installed a new carb on my starboard engine it won't make full power under load. Once the other engine helps pull it up on plane it will go to ~ 4800RPM @ WOT, the throttle linkage opens all the way (I've had other operators run the controls on the water while I'm in the engine compartment) BUT it cuts out- vrooooooom (normal), then goes mmmmmmmm (drops several hundred RPM) and repeats. I have the other one on my port engine (same engine) which is using the same fuel.

I've replaced fuel pump, fuel filter, new OEM Delco gapped to .045 plugs, new OEM wires, new ignition coil. Verified the firing order, timed it to where the manual wants it ~ 6DBTDC and it STILL cuts out and won't make full power.

Thanks in advance!!
M

 

[jimmbo]

Is the timing advancing as the Rpms increase?
Pull the Distributor Cap and Twist on the Rotor, there should be some Rotation, and it should spring back. Remove the Rotor, and check for wires with skinned Insulation

Does you engine have the Backflow Preventers in the Y Pipes?(some VPa have them, others don't) If they are stuck closed or partially closed, they will create Back Pressure, also if they break loose they can Block the Exhaust Passage

 

[Scott Danforth]

Compression was 195 on all cylinders but one at 180- spec is 15% of top compression, so that's good. We timed it too.

Check your gauge. New motor is only 150 psi

 

[ta79pr]

1, agreed with the stuck flapper hypothesis in the exhaust for that motor (if equipped). 2nd, are you sure you got the correct marine grade ignition module? I say that not to be snooty on auto versus marine parts, but the auto version of that EST ignition module does not have the correct timing curve, amongst other issues. I recently ordered the A-Team branded distributor and although listed as marine and with good reviews it came with an automotive module, had to return.

 

[Lou C]

Start at the beginning of the fuel system, anti siphon valve on the fuel tank, & fuel tank vent.
If the anti siphon valve is corroded internally and sticking, or is partially blocked with crud this can happen
When you installed the new Holley, did you check the float setting? Their quality control in my experience is not the best.
What kind of fuel filters are you using? Have you dumped out the filter and checked what the fuel looks like? Sometimes a bit of grit gets past them and can cause the needle valve in the carb to stick.

 

[tampamatt502]

1, agreed with the stuck flapper hypothesis in the exhaust for that motor (if equipped). 2nd, are you sure you got the correct marine grade ignition module? I say that not to be snooty on auto versus marine parts, but the auto version of that EST ignition module does not have the correct timing curve, amongst other issues. I recently ordered the A-Team branded distributor and although listed as marine and with good reviews it came with an automotive module, had to return.

This is great insight, thank you! The ignition coil I bought is the specific Volvo part # - the distributor I ordered is this one from A-Team, should I cancel that and send it back?
Which distributor did you go with that worked for you?

Amazon.com

A-Team Performance - EST Marine Electronic Ignition Distributor EFI - Compatible with Mercruiser Chevy Volvo Penta OMC Indmar 18-5513, 18-5476, 807964A1 V6 4.3L Red Cap​

 

[tampamatt502]

Start at the beginning of the fuel system, anti siphon valve on the fuel tank, & fuel tank vent.
If the anti siphon valve is corroded internally and sticking, or is partially blocked with crud this can happen
When you installed the new Holley, did you check the float setting? Their quality control in my experience is not the best.
What kind of fuel filters are you using? Have you dumped out the filter and checked what the fuel looks like? Sometimes a bit of grit gets past them and can cause the needle valve in the carb to stick.

Hey Lou, thanks for your comment. I've got two engines on the boat, the Port engine is working fine and they're pulling fuel from same tank. It does make me wonder about the carburetor though- I think I should swap the carbs and see if the issue jumps to the other engine.

I have not checked float, I will add that to the list. Fuel filters are new with the carb change- Sierra. I will check the needle valve too.

Also- At idle NOT under load it doesn't cut out at all, sounds great all ranges of RPM. Only under load does it do this crazy thing.

I really appreciate your and everyone's help on this!

 

[Lou C]

How are the 2 engines plumbed from the tank? Two lines coming off the tank, one for each engine? I've never had a twin engine boat but I think with 2 separate lines each should have their own anti-siphon valve. The whole point of it is, to prevent fuel from siphoning out of the tank if the fuel line from the tank to the pump/filter leaks.
Another clue....look at the spark plugs, from one engine to the other compare the plugs from the problem engine to the one that runs well, that may give you a clue as to if it is running too rich, or too lean
One last point, the Holleys use electric chokes, if the power to the electric choke is intermittent, or interrupted, the choke will close, and the engine will be then running way too rich. Might check that first. Remove the flame arrestors and start engines, let them warm up & watch the choke valves. Then after running, stop, shut down and check the problem one. Could be something simple like that.
Electric choke is better described as electric UN-choke!
I actually prefer the old-fashioned manifold heated choke on my Quadrajet. They open slower but do not close if there is an electrical issue.

 

[jimmbo]

Is the timing advancing as the Rpms increase?
Pull the Distributor Cap and Twist on the Rotor, there should be some Rotation, and it should spring back. Remove the Rotor, and check for wires with skinned Insulation

I was assuming a Mechanical Advance Dist, as that is what my 2002/2004 5.7 has, forgetting that Electronic Advance is likely what yours has.

 

[tampamatt502]

Oh yeah, old school here. It’s delco EST ignition, no points. Cap and rotor though.

 

[Lou C]

I'm one of the few who has an old breaker points & mechanical advance distributor you can check it with an advance timing light....
old school tune up circa 1966 tech lol. Glad I didn't throw out my old tools. I have a couple of spare 4.3 distributors, new points plate and new advance springs.

 

[Lou C]

PS
I'd like to see what the spark plugs look like, good engine vs the one that is surging.
blistered white electrodes, fuel starvation...float too low....anti siphon clogged...
black electrodes, maybe choke not staying open float too high, grit in needle valve
one last thing I'm assuming electric fuel pumps, have you checked fuel pressure? Only 5-7 psi need for a carbed engine.

 

[tampamatt502]

How are the 2 engines plumbed from the tank? Two lines coming off the tank, one for each engine? I've never had a twin engine boat but I think with 2 separate lines each should have their own anti-siphon valve. The whole point of it is, to prevent fuel from siphoning out of the tank if the fuel line from the tank to the pump/filter leaks.
Another clue....look at the spark plugs, from one engine to the other compare the plugs from the problem engine to the one that runs well, that may give you a clue as to if it is running too rich, or too lean
One last point, the Holleys use electric chokes, if the power to the electric choke is intermittent, or interrupted, the choke will close, and the engine will be then running way too rich. Might check that first. Remove the flame arrestors and start engines, let them warm up & watch the choke valves. Then after running, stop, shut down and check the problem one. Could be something simple like that.
Electric choke is better described as electric UN-choke!
I actually prefer the old-fashioned manifold heated choke on my Quadrajet. They open slower but do not close if there is an electrical issue.

Good call on the choke, it’s been problematic on my old carbs. I’m just going to disconnect it, we don’t need choke here in Florida but maybe 1 day a year.

There are individual lines from tank to engine, but I don’t think there is anything in-line between the out from tank and in to fuel filter assembly. I’ll check it though, makes sense. Thanks again, you all are great!

 

[Lou C]

If the fuel line dips below the level of the tank, an antisiphon is required.
On my boat this was a problem, the engine would start and rev in neutral just fine but would not plane out the boat. I went through the ignition and carb, nothing really amiss, took it to a good marine mechanic and that's what it was. The boat builders sometimes use a cheap one that corrodes, he put in a better quality one and it's been fine since 2004!