2005 Volvo Penta 5.7 GI Bog/Backfire under load

gregd123

Recruit
Joined
Apr 17, 2012
Messages
3
Hi,

I have a 2005 Four Winns 210 Horizon with a Vovlo Penta 5.7 GI engine and duoprop outdrive. There is ~190 hours on the engine. The engine serial number is 4012132972.

Had the boat out for a week long houseboat trip on Lake Powell. Ran fine for the first three days. Went to the marina day 3 and put ~46 gallons ethanol blend fuel in a 50 gallon tank. First time we ever ran it that low. Anyways, ran fine rest of day (~2 hours run time) with various starts/stops sightseeing on the lake. Brought back to the houseboat and let sit for about 1 hour. The troubles began at this point. Under load at about 1500 rpm backfires and no power. Seems to be running rough at idle but in neutral, can rev engine to 3k+ with no backfire and engine "sounds" good. Here is what has been done by me and the non-volvo mechanic at the marina:

1. Changed fuel-water separator. Did not dump into glass to check for water. Oops. Pulled separator a second time later in the process and did not notice any water in the separator.
2. After replacing the separator, bled 1 gallon of fuel from the schrader at the bottom of the fuel pump and 1 gallon from the schrader on top of the engine between the pump and injectors.
3. Pulled plugs and noticed fouling on plugs 2 and 3.
4. Drove ~30 miles at top speed of 8 mph to marina mechanic. Ran at ~40 and ~140 oil pressure and water temp pretty much the whole way.
5. First thing mechanic did was hook up fuel pressure gauge to schrader on top of engine. Recorded ~52 psi (not positive psi is correct units but he said pressure was normal) at idle and under load. Mechanic said based on his ear, engine was only running on 6-1/2 cylinders and that the back fire was a "lean" backfire.
6. Mechanic checked compression on all cylinders and said compression was good. Also checked for spark at each plug. All good.
7. Marina mechanic did not have a code reader for Volvo engines so at this point they gave up. Asked them to replace the plugs just in case a bad plug was causing the miss-fire.

The two mechanics I talked to back home (southern california) both said ~$95/hr and 2 hour minimum to start diagnosis. They said this would include identifying any DTC's from the ECM.

I have not run on a separate day tank. Not sure if this make sense since I am not seeing water in the separator and fuel pressure is good. One thing, I did notice ongoing air when bleeding the fuel system from the top schrader. I was using a make shift length of hose that fit snug over the schrader but was not super tight. Thought air might be coming in from the connection and thought 1 gallon (step 2 above) should be sufficient to bleed the system.

Any thoughts on trouble shooting steps I can perform or should I take to mechanic and see if there are any DTC's?

Thanks in advance for any input.
 

davidlees

Seaman Apprentice
Joined
Jun 21, 2012
Messages
30
Re: 2005 Volvo Penta 5.7 GI Bog/Backfire under load

I just had my fuel pump unit replaced,(motor had quit) but it bogged under load and had an erratic hard backfire after the new pump was installed. It would run fine at low RPMs and low speeds but if you gave it a quick full throtle it would then backfire. The mechanic said it was a lean backfire. He pulled the injectors and thay did have paint particles in them from the inside of the old fuel pump.He cleaned the injectors, problem corrected.
 

gregd123

Recruit
Joined
Apr 17, 2012
Messages
3
Re: 2005 Volvo Penta 5.7 GI Bog/Backfire under load

So, ended up taking to the mechanic and diagnosis is the plastic distributor is broken. Vovlo part cost is ~$700. Found a couple of aftermarket parts ranging from $120 at http://www.marinedepo.com/vortec.html to $375 http://marineengineparts.com/shopsite_sc/store/html/page729.html#5436 and both of the aftermarket parts also include the rotor, and cap. Anyone have any experience with using aftermarket distributors? Also, how hard is it to replace the distributor. Does the cam shaft sensor deal with all of the timing issues so that it is as simple as unbolting and replacing or is there more to it?

Thanks in advance for any input.
 
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