On the lake - sputtering - anything to try?

[superbenk]

On Beltzville lake right now (3:40 pm, June 4th) & the boat is sputtering at high speed. I suspect something with the fuel system. Anything I should try well I'm out? I have a small socket set and some electrical tape.

Put in a quarter tank on the way up to fill it. Other 3/4 is from last year, but has stabil added. Ran ok at first then sputtered when we were cruising.

 

[ezmobee]

Re: On the lake - sputtering - anything to try?

I'm going to move this I/O where you'll get a faster response. Ben, refresh the guys memory as to what motor you have.

 

[superbenk]

Re: On the lake - sputtering - anything to try?

Running a 1980 OMC 140 w/ Rochester 2bbl carb & Stringer 400. Pics linked in my signature.

 

[superbenk]

Re: On the lake - sputtering - anything to try?

Wondering just how quick iBoats can be in a pinch

 

[smarks]

Re: On the lake - sputtering - anything to try?

Can you check the fuel filters to start with?
Steve

 

[superbenk]

Re: On the lake - sputtering - anything to try?

Can you check the fuel filters to start with?
Steve

Replaced the filter after the last trip & cleaned the strainer at the carb too. Noticed gas was kind of green/blue & wondered if that was bad or just the sta-bil?

 

[Howard Sterndrive]

Re: On the lake - sputtering - anything to try?

could be the ign. coil on its way out

 

[Rocky_Road]

Re: On the lake - sputtering - anything to try?

Replaced the filter after the last trip & cleaned the strainer at the carb too. Noticed gas was kind of green/blue & wondered if that was bad or just the sta-bil?

Sta-Bil doesn't change the color when used as directed.

Is your tank fiberglass?

 

[superbenk]

Re: On the lake - sputtering - anything to try?

could be the ign. coil on its way out

Replaced coil before this trip too (and plugs, wires).

Fuel tank is aluminum & we redid fuel line & cleaned out pickup, etc. At the end of last season. I could be mistaken about the fuel color, so don't put too much weight in that.

 

[smarks]

Re: On the lake - sputtering - anything to try?

When you say "sputtering at high speed" is it cutting on and off or surging?
Steve

 

[superbenk]

Re: On the lake - sputtering - anything to try?

When you say "sputtering at high speed" is it cutting on and off or surging?
Steve

It would hesitate and bog down as if it were suddenly starved of fuel and/or spark. Then it would pick up for a bit and then do it again. The longer we went (holding at around 4700 rpm), the more frequently it'd sputter and bog. While I still noticed it, it was much less apparent under 3000 rpm.

I've been through just about everything electrical (distributor, cap, rotor, points, condenser, plugs, wires & coil - all changed between the winter & today). On the fuel front, I've replaced the fuel line, cleaned the pickup, replaced main fuel filter (twice just to be sure), cleaned the strainer at the carb & rebuilt the carb.

I've also bought a dwell meter & checked that as well as set the timing (again, all this just recently before today's outting).

Really frustrated and not sure what to attempt next. Should I rebuild/reclean the carb again? Should I be concerned about my fuel pump (& if so, how do I test)? Am I missing something electrical? I feel like I'm REALLY close to having a decent working boat, but something is elluding me. Certainly ruined my mood for the day.

 

[Howard Sterndrive]

Re: On the lake - sputtering - anything to try?

I see no mention of the anti siphon valve in the tank being checked....

certainly a possibility

 

[superbenk]

Re: On the lake - sputtering - anything to try?

I see no mention of the anti siphon valve in the tank being checked....

certainly a possibility

I know I checked it when I did the fuel line. but I can't remember if I replaced it or not. I'll dig through my records on that.

 

[ENSIGN]

Re: On the lake - sputtering - anything to try?

You have the classic symptom of water in the gas.Pump some out of the tank into a clear container,if it's cloudy or water at the bottom pump out the tank.

 

[Howard Sterndrive]

Re: On the lake - sputtering - anything to try?

we redid fuel line

at wot, you need a lot of fuel.... any kinks or barbed connectors used that might be restricting flow could contribute

when I converted one boat from a 120HP 4 cylinder to a 185HP V6, it would "run out" of fuel in about 45 seconds at WOT. had to go to a bigger line from tank to filter.

 

[cr2k]

Re: On the lake - sputtering - anything to try?

Also check your fuel pump pressure. Could be going bad.

 

[smarks]

Re: On the lake - sputtering - anything to try?

Also check your fuel pump pressure. Could be going bad.

I'm kinda thinking like cr2k, possibly low fuel pump pressure or maybe sticky floats but you said you had rebuild the carb. Were the floats adjusted during the rebuild?
Regards
Steve

 

[superbenk]

Re: On the lake - sputtering - anything to try?

I adjusted the floats as per the instructions when I rebuilt the carb. Fuel line was replaced a year or two ago. I replaced it with the same diameter tubing that was on there already. I guess I just assume that was proper for the boat.

I was thinking of buying a fuel/water separator and running it inline between the tank and the pump. I know the ethanol gas has a tendency to absorb water more easily, so maybe I have some condensation or something pooling water in the tank.

I need to research what I can do to test the pump itself. It's a mechanical pump, so I assume if it's getting weak that there's a diaphragm inside it that could be worn out or something? Are these serviceable? Does the arm on the pump that runs against the crank just wear out over time making it pump weaker?

I thought I might try running it directly off a 5 gallon portable tank with fresh gas too and see if it does any better.

All this stuff is great, thanks & keep any ideas you guys have coming! Just sucks that the nearest lake is an hour & a half away or I go to the Delaware with all it's traffic & currents that's still 45+ mins away to test.

I did notice the idle was a bit rough too so maybe that's related. I'm sure wet gas would cause noticeable problems with that too?

 

[fossill]

Re: On the lake - sputtering - anything to try?

Should I be concerned about my fuel pump (& if so, how do I test)?

Do google search and a ton of info with pictures comes up on how to do that.
Easier to do that than explain it here.

 

[windsors03cobra]

Re: On the lake - sputtering - anything to try?

Sounds fuel related to me and yes the ethanol is hygroscopic and does attract water.

I wish I would have taped my fuel tank vent off over the winter. I have not fueled mine up for the season yet but put it away with about a 1/4 tank. I'm going to put a bottle of red HEET in it first and then fuel it up.
Next year I will tape my tank vent over to prevent this crap ethanol gas from attracting as much moisture as it does.

I noticed in your pictures that your fuel pump looks to be original and I am in the same boat with my 33 year old MerCruiser and I'll tell you what I am replacing my fuel pump before hitting the water this season. 33 years pumping fuel and yes there are rubber diaphragms inside the pump that make it pump.
The rubber is more than likely not compatible with ethanol garbage and I'm sure the ethanol has not been friendly to that rubber. I was going to suggest you look at your carb but you said its rebuilt.
I would check gas and go ahead and 86 the old pump, $115 for a new pump from what I can see. I'm ordering mine now.

Good luck to ya.