12 Hp Sears - Won't start - Need suggestions

PurpleDragon · Jan 16, 2002

Hello all, You may remember my Sears 12Hp (1965 mfg. by West Bend) that you helped with when I couldnt get the flywheel off about 2 months ago. Up until 2 weeks ago, I had been running the motor weekly in a tank, just to keep things running good until this spring when I can get out onto a lake. Then last week, I pulled that #@#@ cord all day, trying to get it started - but could only get it to run for 5-15 seconds at a time, and it would immediately die. Here's the things that I've checked: - I've got spark on both plugs - Resistance from both plug boots to ground is in the 7150 ohm range - resistance from both open contact points to ground is .7 ohms - compression is still at 60 on both cylinders Today, I changed the fuel pump diaphragm and associated gaskets, thinking that maybe it's fuel starved, and the 30 year old pump probably needs renewing, anyway (and it did need it). Still no dice on getting it to even act like it *wants* to start, though. I'm still thinking it's fuel supply related, but can't fugure out where. It's got a Tillotson T127B carb on it. And lately, it looks to have fuel accumulating at the air intake oriface. (See pic at the following link) Rex's Boat Problem Page There is also lots of oil in the water. So I think the pre-mix is making it through the exhaust to my tank. My arm's sore. And I'm frustrated. What to do next? Order a carb kit for my tillotson? (And the dang thing ran great 3 weeks ago!!!) Any suggestions? Rex S. Rex's Boat Problem Page

PurpleDragon · Jan 16, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Forgot to mention - I've also tried spraying some pre-mix into the spark-plug openings. That only accomplished making my arm more sore. Still won't start. Rex S.

12Footer · Jan 16, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Yes, Rex. You may need the carb kit. But first, check the compression. If it is ok, Does the fuel accumulate when the primer ball is squeezed? If so, it is a stuck float needle. If it just accumulates when the engine is pulled thru, it's drawing WAAY too much fuel. turn the mixture screw (above the thottle body) clockwise until it bottoms out (do not tighten), then back out 1 and a half turns. If it is still drawing too much fuel at that setting, the jets or one of the orifices is plugged, allowing it to be drawn straight from the bowl with mixing with air. This is where I staerted to look,( blocked air orifice) if the mixture screw adjustment does not help.

PurpleDragon · Jan 16, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Yes, 12Footer, the compression is at 60 psi on both cylinders, which is where it was when I had the motor running several weeks ago. I have adjusted the carb mix screw to 1-1/2 turns from completely in... no dice either. I'm starting to suspect that there may, indeed be some blockage in a jet or oriface. Especially after seeing the condition of the fule pump diaphragm after removing it. There was a tear in the center of it, but it was also cracked all over. Maybe particles made it through to the carb & clogged something? Yes - the fuel accumulates both when the primer bulb is compressed, as well as when I pull the cord. I've never done a carburetor job before, but I am willing to take a shot at it. Is there anything I can try before buying a rebuild kit? Any ideas on what a rebuild kit should cost? (Tillotson MD-127 B) Thanks, Rex S.

PurpleDragon · Jan 17, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

I just got off the phone with Discoutn Marine - the guys who generally can provide parts for my older motor... However, they tell me that the carb rebuild kit for this carb is obsolete, and is no longer available. Go figure - my luck. He suggested that the carb be taken apart very carefully, soaked overnight in an automotive carb. cleaner, rinsed real well with water, then re-assembled. Can this be done without a rebuild kit? What all generally comes with a rebuild kit? Thanks in advance! Rex S.

G DANE · Jan 17, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

PD I think you can clean the carb without gasket set, if you disassemble very carefully. To mee it sounds as some little bit of material is stuck in the flouter valve in the carbureator. A new valve is a part of a rebuild set, but if your carb has functioned well, it must do again after a cleaning. But fuel will be injected directly to your one cylinder if there is a leak in pump diafragm.

PurpleDragon · Jan 17, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Thanks G. Dane, Yes - The motor has run fine in the past - so That's what leads me to believe it's a blockage in the carb. I spoke with the fine folks at Certified Parts Corp, and they had the same response - that it was no longer listed in their parts books. My quandry is this: With no rebuild kits available, and if I take the thing apart to clean it... How am I to replace the gaskets? Should I simply cut my own from gasket material? I've done this before, during an head-gasket replacement on an auto repair, but not for a carb. It looks to me like the carb cleaner is some nasty stuff, leaving everything down to bare metal. Should I be using that stuff with the gaskets & float still there? The fuel pump diaphragm that I replaced yesterday had a tear in it, and was cracked all over from sitting for 30 years. I'd imagine that when I ran the engine, the compression pressures eventually blew a hole in the 30-year old diaphragm... crud from the diaphragm went through to the carb, and the lower cylinder was flooding with pre-mix. Thanks, Rex S.

12Footer · Jan 17, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

The imerssion type carb cleaner is wicked stuff. Do not use it,unless you intend to replace every piece of plastic, rubber, and non-metal element of this carb. Some Tilotsens, (like those used on the 50HP Force), even have rubber-tipped float needles. You can buy an exacto knife, and make your own gaskets without too much hastle. Just be sure to punch-out every hole the origninal gasket has in it (like the small overflow hole above the body on the intake gasket). But if you can squeeze the primer, and get gas to run out of te carb anywhere, your primary problem is the float needle valve sticking open. Sometimes tapping the side of the bowl while squeezing the primer will "unstick" it. This will get you home if it were to happen on the water, but I wouldn't count on it as a perminent fix. The carb must be removed, float hinge pin pulled, and the needle cleaned with spray cleaner to remove any varnish on it. There may also be a rubber O-rng in the needle vave's tube at the seat. Leave it be, unless we can find a kit for th carb. Naturally, you'll want be assured all the ports are clean and open before re-assembly. Let us know how it turns -out, or if you have any questions durring teardown or assembly. Also, I'll see if I can find a source for the kit tonight.

PurpleDragon · Jan 17, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Thanks, I'll keep the message board active with any probs or updates on the matter. I'll most likely start on the project on Saturday morning. Rex S.

12Footer · Jan 17, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Ok, Rex. This site has yourt carb kit listed for 12 bukz. Don't know if it actually in stock,but it IS listed. http://www.laingsoutboards.com/newpage5.htm

PurpleDragon · Jan 23, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

I am waiting on the gasket kit on my carb to show up - but went ahead today and took the carb off the motor. Guess what I found INSIDE the bowl? The inlet jet screw and it's brass washer! The .049 jet was laying there. The motor was literally flooding, and couldn't start. Replaced the screw & washer, cut new gaskets, and reassembled. Pumped that bulb up, pulled the crank, and Vrooommmmmm!!!!! Gotta say - it doesn't smoke NEARLY as much as it had in the past, and there's now very little oil residue in the tank of water from the exhaust. Yep - I was a 'bit skeered' to go into a carb - but wouldn't think twice about it, now. Thanks guys! Time to hit the water in the 'ole boat! Rex S.

12Footer · Jan 23, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Glad to hear it, Rex. Congrats on the successful repair

ICEMAN · Jan 23, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Hi Purple Dragon, Here's a possibility of somewhere to get parts for that carburetor. Your local lawnmower repair shop. Some of the parts used in the sears outboards are used in lawnmowers also. You may have to bring the part and inquire, But I've had luck getting parts for them that way.

harrison20002 · Jan 24, 2002

Re: 12 Hp Sears - Won't start - Need suggestions

Amen Iceman on the small engine shop. I live quite a ways from a Marine Supply so I try our local small engine shop. I have been lucky enough to find carb. kits, fuel pump kit and a few other goodies from time to time. Also check with your local Napa Auto parts houses. Most of them seeem to be able to order marine parts. Remember Guys, the days are getting longer, Happy Boating! Hal

12 Hp Sears - Won't start - Need suggestions

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