Carb question for you gassers out there

[bufferoo]

I have a homelite chainsaw that I have salvaged the engine from. The engine ran GREAT last fall. I had to get a new saw after cracking the case in the move. The case if fine as far as the engine running, I just can't have a gas or oil tank. ;) Parts cost as much as a new saw.

So I have a good engine sitting there. Or so I thought. As I said it ran great last fall but now it bogs down severly at any more than 1/2 throttle, and raw gas spits out the carb. It doesn't matter how hot it is and this is fresh gas running at 50:1 (homelite specs).

It has a ZAMA (never heard of that one) carb with high and low mixture screws. I played with both and saw no change.

So my question(s) are have any of you seen this before and if so what should I do now?

I hope to mount this in a gatorbait that I made this winter. I already have an engine for that but it's a 22cc and it has a bit of trouble turning the 18" prop at full speed. I'm sure the 33cc will do much better. :)

Thanks.

Bufferoo

[FlyerCAN]

sounds like its way too rich, but you say you did all you could do with the needles. Are they marked in some way as to high and low? the low is for setting the idle so if it idles fine then the L is ok. rev it up and lean out the H screw till it screems then open it till it slows a bit. So it will be on the rich side of the curve, but if I am to assume you already know this then I have no other solution, but to go with another carb.
Hope some of this will help.

[bufferoo]

Seeing as I want this to be as budget friendly as possible, I REALLY don't want to have to change the carb.

I just can't figure out what could have happened over the winter. It was run dry. Stored indoors in a clean dry place. Cleaned off before storage.

The carb does have an idle stop screw and I did have to adjust that a bit just to bring the idle up a tad. There are 2 screws for mixture adjustment; one for high and one for low. They each only turn a 1/2 turn. I tried running the engine at full with the needles turned full left and then full right and all settings in between. No change at all. It does seem way too rich to me but it just won't seem to change. I guess I'll have to do a full teardown on it to see what the issue is.

Thanks.

Bufferoo

[Doubledog]

Humm.
Have you posted this on Jims? I sure ain't no carb mechanic.

[FlyerCAN]

just thought about it... the float may be stuck! The jet may be wide open inside.Take the carb apart and loosen up all moving parts. It happens when an engine sits for a long time with gas in the carb.

[Chris LaPanse]

18"????????
That sounds like the prop turned by a 365ci V8 in my aunt's full size boat. As far as carbs go, i have no idea, unless it is running rich. Also, 50/1 sounds a bit low on the oil content. I run more like 25/1 or 30/1

[bufferoo]

Yeah...I'll pull the carb this weekend and see if anything is moving that shouldn't or if anything that should move doesn't. :(

I can get the 18" prop up to 5876 rpm on the 22cc engine. I'm looking to get a steady 7k. I figure the extra 11cc should do that. ;)

50:1 shold be right on. It's the homelight oil that cam with the saw and it's right on with the specs in the manual. I have run 32:1 but it would foul the plug something fierce.

About all I can figure is that it's as rich as can be. Worst case scenario I replace the carb. Kind of a bummer though. That's $ that can be put to better uses. Like props or glues, or tools or....better stop there. Gonna get myself all worked up.

Bufferoo

[FlyerCAN]

But really!! 18" means 18 inches. Thats a big prop for a 22 or 33cc

[bufferoo]

Sure an 18 inch prop is big but I've been with flyers that are running 24" & 28" props 42cc engines. And these were 6, 8 & 10 pitch props at that. Sure these are not as high reving as the smaller nitro...that's why we can go with a larger diameter. It's not about speed when you're going big, rather the thrust. At least that's what I've always been told.

My gatorbait swings the 18x8 prop at a high 5k. It weighs in at almost 15lbs and still goes like stink over grass, sand, & water. Forget snow and ice. Can't even go over half throttle there. The problem is in the takeoff from a dead start. It takes too long for the engine to rev up and so the boat doesn't move too quickly from a standstill. So I tried and 18x10 and it has the same issue, sort of. It will start off faster but full speed is reduced.

Enter a bigger engine. After all, isn't that REALLY the goal we all have in the hobby?

Boat too slow, get a bigger engine. Engine too big for the boat, get a bigger hull. More hull than engine, get a bigger engine etc until we get to the point where it just makes financial sense to buy the full sized job and scale back to .12 sized hulls.

That's my goal.

Buferoo

[bufferoo]

Well she's workin'! Turns out it was all my fault and apparently I'm just a big ol' dummy at times. Seems the clutch was all clogged with oliy sawdust and it was causing a whole mess of drag keeping the engine from reving up. Add to that the fact that the carb it uses has a special feature where when you go to WOT quickly it injects a nice shot of gas to help the accelleration.

So, cleaned out the clutch and she runs like a dream again. Starts on the first pull and idles rock solid.

Mind you it's not going to make it into the gatorbait as planned. Picked up an older 35cc craftsman engine a while back that will do the job nicely. I've just never done anything with it.

So it seems that I have an extra engine (again :D ). What to do? What to do? ;)

Bufferoo

[Hydro Junkie]

Sounds like it's time to build something else to put the extra motor into :D After all, having an unused motor lying around is both a waste of space and material :( Maybe a 1/5 or 1/6 scale HYDRO :D Better yet, a TURBINE HYDRO :D Or faster yet, an outrigger HYDRO :cool: Or maybe....................

[BoatDoc]

i know that feeling...i've got a fully modded 3.5cc outboard sitting around. it's ported, polished, exhaust throttle...you name it...just need a hull!!!!

[Hydro Junkie]

Can we say OUTRIGGER!!!!!!!!!!!! :D

[BoatDoc]

i've been thinking about that outboard 'rigger from prather. but i'm holding out for something better.

[dannyUAL767]

Is there anywhere to buy a large, wood outrigger kit that isn't one of the high dollar pre-assembled boats that many of the racers are using? I don't have that kind of coin :( . Besides, I enjoy building boats myself. I was thinking about buying a Dumas Hawk 7.5 and then tracing all of the parts prior to assembly. Then I'd get the tracings enlarged so that I could "scratch" build a hull about 1/3 larger.

[Hydro Junkie]

I'd do exactly what you just described, with a twist. Fit the parts and trim them so they are fairly close to the right size and shape, then trace them :cool: . When you enlarge the tracings later, you will have considerably less material to remove during construction, meaning a faster build :) . It will also mean less waste, as Dumas parts are notorious for poor fit, the prefitted tracings will need very little trimming and fitting :D