3.0 Volvo Penta Power Loss at High Speed

[larson186]

Oh Boy!!! I had aquired last year a 1996 Larson 174 17 ft bowrider equipped with a Volvo 3.0L 135hp I4 engine in excellent condition. One problem however continues to plauge me during my outings. While on plane at 4000rpm and after about an hour or so of operation the engine gradually loses power, sputters and quits. All other engine indications are normal (eng temp 150-160, oil press and voltage). After sitting for about an hour and a half (fishing while waiting) it will start with no problem. I noticed the fuel line running from the fuel pump to the carb (A Holley 2bbl) is metal and runs along the lower end of the block up around the head to the carb REAL close sometimes in contact with those components. Could I be suffering from fuel vapor lock? And is there a suitible substitute for the fuel line?

 

[rattana]

Re: 3.0 Volvo Penta Power Loss at High Speed

Either that or your gas tank isn't venting. Check your vent tube for any obstructions.

 

[larson186]

Re: 3.0 Volvo Penta Power Loss at High Speed

Thank you for the timely response. Vent tube is clean and clear still having same issue. I did check to see if fuel was making it to the carb and it is after this last stall. A friend who was out with me has a hunch that the ignition coil may be getting hot and making the ignition fade as the temp increases seeing how it is mounted so close to the engine or the coil is ready to fail all together.

 

[pine island fred]

Re: 3.0 Volvo Penta Power Loss at High Speed

check and see if there is a finger filter screen in the fuel pick up tube in the gas tank. they get clogged quite a bit. fred

 

[hoot]

Re: 3.0 Volvo Penta Power Loss at High Speed

most likely a bad ignition coil. i did cover my fuel line with aluminum foil to reflect some of the heat in the 'doghouse'. don't know if it really helps, but it is an interesting conversation starter.

 

[larson186]

Re: 3.0 Volvo Penta Power Loss at High Speed

OK, Larson built a rather tight product, hull wise. The fuel tank is very well packed in and I have followed the supply line to the tank, but I can't get to the filter. My next plan of attack is to disconnect the fuel line from the pump and blow air back through it to the tank. Also incase nobody knows, long threaded spark plugs also don't work well in this particular powerplant. Champion 401's are about the best application other than the Volvo ones. Seems they cause pre-detonation and higher than normal spark and they burn off too. Another thing I have learned is that the ignition on this powerplant is electronic and is more apt to dieout all together than have a power fade say from fuel starvation. More to come after I return from the west coast.

 

[DHPMARINE]

Re: 3.0 Volvo Penta Power Loss at High Speed

Davie,does the motor crank and not start?<br />Or does it not crank?<br />DHP

 

[xltier]

Re: 3.0 Volvo Penta Power Loss at High Speed

lots of boats have a one way check valve in the line entering the tank.if it does u wont be able to blow back thru it.those get corroded up bad.unscrew it from the tank and ckeck.many a fuel pump been replaced cause of that.hth

 

[Gasoline]

Re: 3.0 Volvo Penta Power Loss at High Speed

My 3.0LX Mercruiser exhibited a very similar behavior two years ago. Turned out to be a bad electronic ignition module inside the distributor failing when it got hot. Got a new one from a local auto parts store for just a few bucks.

 

[larson186]

Re: 3.0 Volvo Penta Power Loss at High Speed

Greetings all,<br /><br />Sorry for not replying I was out of the country for a bit. Thank you for your input on my subject problem. I did check into the fuel system and got a rather rude awakening. First the fuel was 3+ years old and needed to be purged, engines don't run well on bad gas, this in turn led to the discovery of the pick up filter (strainer) partially blocked with dead bugs. It also allowed me to inspect the check valve which was like new. The engine does turn over and fire runs great at idle and high rpm but only about 45 minutes. I did invest in a Clymer maintenance manual and highly recommend anyone who is remotely mechanically inclined pick one up, very informational. To make a long story short the root cause ended up to be the ignition coil and combination with the wrong spark plugs. The boat runs fine now and have enjoyed it since the repair. Again thank you all for your suggestions and input.

 

[texsun]

Re: 3.0 Volvo Penta Power Loss at High Speed

I've got the same Larson Boat. I know exactly what you mean when you say "rather tight product". I had to change the alternator belt and the starter on mine. Pretty close quarters. Would you be interested in trading emails for "common issues" on our boats?<br /><br />Mark