Penta 350 problems...

[kmfs91]

Hey guys, I'm new here with a couple questions. My dad recently bought a '93 Wellcraft Sport 210. It had a Penta 350 in it, but one of the previous owners failed to winterize it properly and cracked the block :facepalm: So, from what we were told, an early 80's 4-bolt main Chevy 350 was dropped in it's place. And now that I think about it, that doesn't exactly make it a Penta anymore, but I guess I'll ask since I'm already here.

I was out on the boat last weekend with about 10 or 11 of my friends, just doing some wakeboarding, tubing, etc... The boat was running great, until after about 4 hours of screwing around, we were idling waiting for the next boarder to get ready when the engine quit. It was like someone shut the key off. I figured we were out of gas, since we had only put 10 gallons in it and had been doing a lot of full throttle driving with the full load of people. So I dumped another 6 gallons in it, and tried to fire it up. It would fire and die, so I let it sit for a few minutes thinking maybe I had flooded it trying to start it. Well, it kept doing the same thing. Occassionally it would idle, but once you got above about 1,000 RPM, it would start stumbling and die.

I guess I should mention it's just a stock 350 with a Holley 2BBL, so there's practically no electronics on it.

So we sat for another 10 minutes or so, and still no dice. I did get it back up to top speed once, but it took 3 or 4 minutes of stumbling nd sputtering to get there. And once I came back down to idle it started all over again.

Well, the next day my dad and I were checking it out. It seems to be getting plenty of gas through the carb, but it just won't run. And when it does idle, it doesn't sound or feel smooth like a V8 should. And it's not a rough cam idle either.

I was going to pull the valve covers tomorrow and start having a look around, to see if maybe a few pushrods got bent or a rocker broke. Do you guys have any suggestions what might be going on here, or what I should look for?

Sorry for the long first post, I'm just trying to cover all the bases so I know what to look for when I dive into it tomorrow.

 

[captmello]

Re: Penta 350 problems...

before dismantling the motor, I would do a compression test and perhaps check the timing, and the rest of the ignition parts.

It sounds like its not getting enough fuel...Filter perhaps.

Hopefully it's something simple.

Welcome to iboats, btw.

 

[Maclin]

Re: Penta 350 problems...

Pull the spark plugs and look at them.

The carb may have a problem internally with the powervalve leaking, usually that presents as a flooded condition, and once RPM's come up it can run ok, but it can foul the plugs. If the plugs get fouled while idling and trying to start then it will run rough until the plugs can "clear", and sometimes they can't clear themselves when wet fouled like that.

Check out the ignition components and dwell and timing. If your engine used the same Volvo Penta ignition then it won't have points but who knows at this point.

Check all wiring at the coil. Check voltage at the coil.

 

[kmfs91]

Re: Penta 350 problems...

Well my dad and I slapped a new fuel filter on it this morning and pulled the valve covers off to have a look. Everything looked great and it was firing up like it should, so we pulled it to the ramp and dropped it in. I don't know what was up last weekend, but it was running like a champ this morning!! Probably the best it's run since we bought it. My guess is the filter got plugged from running the tank down last weekend. I could be way off, but that's my theory.

Out of the water, it is quite noisy where the engine mates to the outdrive. I grew up with inboards, so the Pentas are new stuff for me, so for all I know it could be the nature of the beast. It pulls hard with the nasty duo-prop setup on it, so maybe it's normal??