A-4 dies at higher RPMs and smokes

[pearsontriton28]

I have an A-4 in my 1961 Pearson Triton 28. As far as I know, its the original engine. All though it has no modern upgrades, with exception to the fuel/water separator, it has been meticulously maintained.

After installing the fuel/water separator and regular weekly use without any problems, I thought my fuel issues were over, until last week.
Here's what I have going on:

-Engine starts easily

-Idles nicely, no "missing" , idles smoothly

- As I throttle a little above idle, the engine looses power as though it is fuel starved. I have no tachometer to indicate at what RPM this starts at.

- I notice it smokes a slight gasoline smelling white smoke out the exhaust as the RPMs raise. very similar to what you smell when you first start a lawnmower.

- I can get the engine to rev significantly and smoothly if I advance the choke a bit.

- I notice the white smoke increases as I throttle it up with the choke advanced.

- I have not noticed a change in oil pressure or level.

With that info in mind, what do you think is happening and how do I fix it?
Do you think the smoke is related to my carb/ fuel issue? thanks in advance.
Edit: I do have a polishing filter in line.

[tenders]

I’d recommend adding a polishing filter and an inline fuel pressure gauge between the fuel pump and the carburetor.

The filter is just good practice and the gauge will tell you whether what you’re experiencing now is a fuel pump problem or a carburetor problem. It could be either, but I’d guess it’s the latter, so while you’re waiting for the filter and gauge t arrive I’d take off the carb and clean it out thoroughly, as described many times here.

[pearsontriton28]

Thanks for answering, I need to edit my original post as I do have an inline polishing filter. I will check into a fuel pressure gage and clean the carb.

[ndutton]

The choke effect speaks strongly to the mixture leaning out at higher RPM. I think if it were a lack of fuel supply (pump, filter) the choke wouldn't make a difference. If it were a vacuum leak I think the idle would be affected too which it is not. The typical problem is a clogged or partially clogged main jet so count me in on Tenders' advice for a thorough carburetor cleaning. If debris is found or if cleaning solves the symptom it will then be time to find out where it came from.

Also, just because it is affected by RPM too, lube the distributor advance flyweights. There's no downside and you'll be sure it's not contributing to the symptom. If at all possible, please do it with the distributor in situ. We don't need to introduce timing issues to the mix.

[JOHN COOKSON]

Originally Posted by pearsontriton28

, I thought my fuel issues(?) were over, until last week.
Here's what I have going on:
- I can get the engine to rev significantly and smoothly if I advance the choke a bit.
.

What were the "fuel issues"? Are they still ongoing or new ones?
With the choke closed a bit the engine revs up in gear or out of gear normally?

TRUE GRIT

[pearsontriton28]

Fuel issues refers to the water accumulation in the tank. I use better gas, start tron additive and I installed a fuel/water separator. I can advance the throttle without it stalling if I have the choke closed a bit. Doesn’t matter if I have it in gear or not. Acts normal with the choke slightly closed.

[capnward]

I agree with the diagnosis of a clogged main jet. In my experience, cleaning the carb and jets, and replacing inline filters, usually fixes the problem. We A4 owners eventually become proficient at this. I have gotten the process down to three hours. I sometimes do it before starting the engine in the spring, to be pro-active. If by 'better gas' you mean non-ethanol, I agree with that, too. Ethanol makes the water in your tank mix with the gas, and degrades the rubber parts of your fuel system, IMO. An enzyme fuel additive like star tron is good, to keep the water in your tank from growing things that clog your fuel filters and carb. I also use MMO, as I think do most of us, to keep the fuel pump and valves lubricated. A water separator is essential. The fuel pressure gauge tells you if there is a restriction in the flow. You may want to consider an adjustable main jet. I have read here of a problem like yours being solved by turning the adjustable jet in all the way to the seat, and then backing it out 1.5 or 2 turns. This apparently clears the jet opening, but it also must send the crud into the carburetor, to possibly clog the idle jet or obstruct the float valve.

[pearsontriton28]

Yes, I use non- ethanol gasoline. I’m going to clean the carb and main jet as you and others have suggested. I will start using MMO as stuggested as well. Do you think the white smoke issue is related or it coinsedence that the carb issue is happening at the same time?

[Dave Neptune]

RE the white smoke, are you sure it is not just steam? Various atmospheric conditions can create steam "showing" in the exhaust. It is always there but may not condense for visibility.

How old is the exhaust? A plugged exhaust can create the symptoms you describe too. This is usually a steady progressive performance issue. Not often sudden unless an exhaust hose collapses on the inside.

Dave Neptune

[pearsontriton28]

You raise good points. It could be steam, but it seems to linger and dissipate like smoke. Last season, I had very little of it. This season, it seems like I have noticeably more. I’m not sure how old the exhaust is. It looks to be in good shape to me. With steam / smoke , I start thinking of the possibility of a bad head gasket or cracked head. Really would like to put those concerns to rest.

[ndutton]

The two concerns you mention can be tested easily with a cooling system pressure test (lots of info on the forum).

[pearsontriton28]

thanks everyone who responded to my post. I wanted to give you an update and an opportunity to further comment if you would like.

I pulled the carb and tore it down. heres what I found so far:

- some surface rust on the bottom of the fuel bowl.

- main jet was turn out 6 turns, I removed and flushed flakes of crusty particulate out of the jet orifice. the PO and now, I am running an inline polishing filter so I doubt the rust came from my fuel tank. I'm thinking it formed inside the carb surfaces as a result of having water in my fuel in the past.

- the main jet itself was dirty - I cleaned and replaced it back out 2 1/2 turns

- the idle needle valve was out 1 turn and was clean. I replaced it back 1 full turn out.

[ndutton]

Originally Posted by pearsontriton28

- some surface rust on the bottom of the fuel bowl - flakes of crusty particulate out of the jet orifice - the main jet itself was dirty -

and the coup de grace

I use non- ethanol gasoline

You mean this wasn't the fault of the oft assumed go-to boogeyman ETHANOL?

[pearsontriton28]

Originally Posted by ndutton

and the coup de graceYou mean this wasn't the fault of the oft assumed go-to boogeyman ETHANOL?

Honestly can’t believe the motor ran with that much particulate in the jet. So the whole ethanol thing came to light in early June when the carb on my lawn mower took a dump on me, mean while, I was having issues with moisture in the A4. The guy at the lawn mower shop schooled me on ethanol and it’s evils. $150.00 down on the counter, a new carb on the mower and he was telling me to use marine gas for the lawnmower because it contained no ethanol, thus drastically cutting down on moisture issues. Ethanol apparently is corrosive to the delicate parts of a small engine carb also. I had an epiphany at that service counter. I was using pump gas in the boat at the time and had no separator because the previous owner didn’t use one- I was sabotaging myself with pump gas which led to water in the gas and ultimately rust in the carb. I have been using non-ethanol gas. . I was too slow a learn on this one I guess. Anyway, I just got back from reinstalling the carb. I’m happy to report that the old A4 runs great and revs nicely. I have significantly less smoke also. Thanks again.

[sastanley]

Hello, I decided to comment on your post because it seems that your lawn mower guy assumes that if you buy gas at a marina, it is ethanol free. In the mid-Chesapeake Bay where I am, I have found ZERO marinas with E-0 gas. There are a few non-marina places (like restaurants with a fuel dock) that do sell E-0, but I generally source my E-o gas from a land based fuel company via jerry cans.

If you really want to make sure you are running E-0 gas, I have found this site pretty reliable.

https://www.pure-gas.org/

Neil and I and others on the forum have gone round and round with E-0 vs. E-10..all good discussion. I prefer to lug E-0 to my boat in jerry cans.

Let's hope the junk in the jet was the issue!

[pearsontriton28]

Originally Posted by sastanley

Hello, I decided to comment on your post because it seems that your lawn mower guy assumes that if you buy gas at a marina, it is ethanol free. In the mid-Chesapeake Bay where I am, I have found ZERO marinas with E-0 gas. There are a few non-marina places (like restaurants with a fuel dock) that do sell E-0, but I generally source my E-o gas from a land based fuel company via jerry cans.

If you really want to make sure you are running E-0 gas, I have found this site pretty reliable.

https://www.pure-gas.org/

Neil and I and others on the forum have gone round and round with E-0 vs. E-10..all good discussion. I prefer to lug E-0 to my boat in jerry cans.

Let's hope the junk in the jet was the issue!

hello, thanks for commenting. living in the great lakes region where trailerable fishing boats are king, we have a gas station nearby that sells "marine gasoline" that may contain .005 % ethanol. I guess this is as close to e free as you can get in my neck of the woods. he was suggesting I go there for gas. Consumer Report is reporting small engine issues with gasoline containing 10% ethanol. The federal government is now allowing up to 15% ethanol in our gasoline. My marina claims to be low to no ethanol. Ive been using that for the boat over the last several weeks and haven't noticed any accumulation of water in my fuel/water separator bowl.

[sastanley]

Roger on all that. It is great that you have almost-no-ethanol sources of fuel. I would for sure use them if they are not too inconvenient.

Marine gas up there is different than marine gas down here..most marinas here have the same E-10 garbage as the Sheetz/Wawa/Exxon car pumps.

[pearsontriton28]

Originally Posted by sastanley

Roger on all that. It is great that you have almost-no-ethanol sources of fuel. I would for sure use them if they are not too inconvenient.

Marine gas up there is different than marine gas down here..most marinas here have the same E-10 garbage as the Sheetz/Wawa/Exxon car pumps.

I'm pretty sure Ive read marine gas can vary in ethanol percentages depending where you go. Your post would confirm that for me. I don't use my lawn mower or boat gas up quickly, so I would have plenty of time to accumulate water in the tank. For instance last season and early this season, before I figured I had a moisture problem and started using marine gas , I observed that it took two weeks between the point of adding a fresh tank of gas and to the point the engine not able to start. I remedied this by emptying the tank, cleaning the carb (with exception to the main jet) and adding fresh gas. I would go another two weeks to no start, then repeat all over again. At the risk of receiving criticism, I have to admit I went through a few of these 2 week cycles before I figured moisture was the culprit. I'm pretty sure all the rust and rust particulate were the result of my moisture issues of last season and early this season. I can see where those who use their fuel quickly so as not accumulate much moisture may not have a problem with ethanol, but as for me, You can place me firmly in the no ethanol camp.

[JOHN COOKSON]

Originally Posted by pearsontriton28

. I remedied this by emptying the tank, cleaning the carb (with exception to the main jet) and adding fresh gas. I would go another two weeks to no start, then repeat all over again. At the risk of receiving criticism, I have to admit I went through a few of these 2 week cycles before I figured moisture was the culprit. I'm pretty sure all the rust and rust particulate were the result of my moisture issues of last season and early this season. I can see where those who use their fuel quickly so as not accumulate much moisture may not have a problem with ethanol, but as for me, You can place me firmly in the no ethanol camp.

Did you clean the tank or just empty it?
Ethanol has a detergent or scouring action in addition to pulling in water. What material is the tank made of? The frequent mention of rust makes me think of an iron tank. This story may not be over yet. Lots of rust will overwhelm the polishing filter quickly. Maybe switching to non ethanol gas will end the problems. Hope so.

In any case good to hear you got 'er going.

TRUE GRIT

[pearsontriton28]

Originally Posted by JOHN COOKSON

Did you clean the tank or just empty it?
Ethanol has a detergent or scouring action in addition to pulling in water. What material is the tank made of? The frequent mention of rust makes me think of an iron tank. This story may not be over yet. Lots of rust will overwhelm the polishing filter quickly. Maybe switching to non ethanol gas will end the problems. Hope so.

In any case good to hear you got 'er going.

TRUE GRIT

Thanks. The tank is made of monel, similar to galvanized. All the rust I’ve found has been in the carb. I haven’t found it in my polishing filter or in the sediment bowel...yet.

[tenders]

After you mentioned that you used non-ethanol gas in your tank, I believe Neil‘s point about ethanol was the ethanol is blamed for all manner of carburetor problems when in fact many of those problems are caused by old components, poor maintenance, or both.

I find ethanol an annoyance that should be removed from the fuel recipe in the first place...but not a hindrance. I use ethanol-laden gas station fuel exclusively in my tank, but treat it with Sta-Bil without fail regardless of the season. In the spring I try to run down the leftover fuel from the previous season before adding fresh fuel to the tank - this year the first time I added fuel was last week. I have a Racor canister filter before the fuel pump and a polishing filter between the pump and the carb. I can’t say I’ve ever had an ethanol issue, and there have been two entire seasons that the boat spent out of the water, 2009 and 2015, unused. Both times after launching the engine didn’t seem to notice the old fuel, although maybe the exhaust smelled a bit funky.

My understanding is that ethanol eventually causes old fuel to turn into an orange goo that doesn’t tend to dissolve in the presence of new fuel. Flakes and other solids probably come from rust and other oxides from decomposing tanks, pumps, hoses, and carb bodies. Perhaps ethanol hastens these problems but it doesn’t exactly cause them.

It doesn’t seem unreasonable that the small carbs on lawn mower engines are particularly susceptible to goo clogging, and that the typical lawn mower owner probably draws from a garage jerrycan of old unstabilized fuel and leaves it in the tank during the off-season. With my small engines I am also hypervigilant about using relatively fresh, stabilized fuel 100% of the time and always drain the tank and carb to empty in the off season, usually with an extra shot of Seafoam in the residual fuel for good measure. (No idea if Seafoam does anything at all, but I consider it more of a solvent than a fuel stabilizer.)

So I would submit that ethanol issues are pretty much non-issues with:
- a clean carb to start with
- constant treatment with Sta-Bil or other designated fuel stabilizer
- reasonable vigilance about using up old gas before diluting it with new gas
- a water separator/filter and a polishing filter

Of course there are other issues that can arise with fuel systems, ie, water in the tank from a failing or nonexistent O-ring around the fuel fill, etc. but again, that’s not ethanol’s fault.

[ndutton]

Yeah, ethanol is often blamed for everything including kidnapping the Lindbergh baby. Perhaps my sarcasm was unclear.

[pearsontriton28]

Originally Posted by ndutton

Yeah, ethanol is often blamed for everything including kidnapping the Lindbergh baby. Perhaps my sarcasm was unclear.

no worries. I guess sarcasm can go unnoticed or misunderstood when expressed through text. I think you have a point with ethanol may be "guilty" by association all too often.

[capnward]

My evidence that ethanol is bad is not scientific, only anecdotal. I stopped using ethanol, and the orange goo in my filters and carb didn't return. That really happened. Maybe by that time, the ethanol had cleaned my tank until there was no source of orange goo left; it all went downstream and stopped my engine periodically, to the benefit of the corn industry. I have never cleaned my tank, except once when it was filled with diesel by mistake by the gas dock guy, then his boss pumped it out. The only time I have old fuel is in the spring. I keep a full tank over the winter, and after using up most of it, dilute it with new gas. I use about 100 gallons a season. I use Biobor JF enzyme additive. I have no experience with Seafoam or Sta-bil, only MMO. Not to worry Neil, the sarcasm was unmistakable. I'm sometimes guilty of that myself.

[tenders]

I'm super fuzzy on exactly what goes into gasoline stabilizer, but I do know that diesel fuel stabilizer contains a biocide that kills a moss or fungus that somehow manages to grow in diesel fuel.

It doesn't grow in gasoline, and diesel fuel additives don't do anything useful for gasoline. Are you sure the Biobor is doing what you want?