Is This A Carb Problem?

crownroyal

Seaman Apprentice
Joined
Mar 2, 2004
Messages
38
I have a 1988 johnson 60 hp motor. It runs fine but occassionally when you give it WOT it sputters but if you push in the key for the choke it takes off. You may go all day and it wont do it at all and the next day everytime you give it WOT it sputters but hit the choke key it takes off and runs fine Ive checked the high speed jets and they look fine. Could it be trash or something in the bowls or other jets. Thanks<br />P.S. i checked the compression and the top reads 110 and the other 2 are around 135
 

bubbakat

Captain
Joined
Oct 29, 2002
Messages
3,110
Re: Is This A Carb Problem?

Do a decarb and see if it will help the compression there is to much of a difference in them. I would rebuild my carbs and check fuel pump to see if it is good.
 

crownroyal

Seaman Apprentice
Joined
Mar 2, 2004
Messages
38
Re: Is This A Carb Problem?

Can you tell me how to do a decarb? What i need to buy and how long it stays in the cylinders
 
D

DJ

Guest
Re: Is This A Carb Problem?

Taken from the FAQ's section.<br /><br />gss036 <br />Captain <br />Member # 18759 <br /><br /> posted November 15, 2003 12:56 AM <br />--------------------------------------------------------------------------------<br />Since this pops up every other day on some board, try this method, I picked it up on another board and have been using it for awhile now,works great.<br />Tip for the Week <br />Do-It-Yourself Engine Tip; A Simple and Cost Effective Way to De-Carbon an Outboard <br />By Capt. Bob Dunkelberger dunk75@comcast.net <br />This works for Carbed, EFI, Ficht, HPDI, Opti-max and even 4-strokes... and should be administered after every 50-60 hours of use. <br />First you need a separate small fuel tank. One of those 3-gallon red Tempos works well or an empty gallon milk jug in a pinch, but it might be a bit messier. <br />I use Seafoam over the OEM (original equipment manufacturer) stuff like OMC Engine Tuner or Mercury Power Tune. Note: in the last few years they changed the formula and you have to let them sit up 12 hours. Who's got time for that? Seafoam does the job in 15 minutes and can be purchased from NAPA, Car Quest or other auto stores. <br />You'll need 3/4 gallon of gasoline and one 16oz can of Seafoam for each engine. Don't forget to add 3oz of oil if you are pre-mixing in a carbed engine. Use a 3 ft piece of fuel hose off the small tank. Connect this tank to your engine by pulling off the main tank fuel hose from the intake side of your water separating fuel filter and plug the hose off the small tank onto that fitting. Or you can separate the fuel line on the tank side primer ball, so you can still use your primer. If your engine has a fuel plug then you will also need a fuel plug on the smaller tank's hose. <br />Start the engine, let it warm up and start pulling the mix into the engine. You may have to increase the idle to keep it running once she gets loaded with the Seafoam. Run the engine 15 minutes at the dock or just cruising around under 2500 rpm's. Then shut it down and let it sit for another 15 minutes. <br />Restart the engine; the smoke you see is the carbon burning off. Do the whole thing again and let her sit again for 15 more minutes. If she smokes after the second time do it again. <br />I've never seen one still smoke after three doses. (I bought a Bronco two years ago that had 95,000 miles on it. When I used Seafoam on it I had the neighbors hanging out of their front doors looking for where the fire was after I started it the first time there so much smoke) <br />The gallon mix should be just enough to do this 3 times. You don't need a wide-open throttle and you don't need to change the plugs. The plugs are cleaned at the same time as the combustion chambers. My suggestion is that every 50-60hrs is the optimal time to change plugs in most engines. <br />I cleaned an antique Evinrude once that had a 1/4" of solid carbon on the exhaust chamber walls by running a 1/2 gal of the aforementioned mix through it. Seafoam, a great product, has been around since the 1930's and it's what they used when they were burning straight 4 stroke 40SAE oils in outboards. <br />For you guys with the 4 stroke outboards? Those engines work 10 times as hard as any auto engine ever will and they too will carbon up. Too many are under the assumption that it's totally the 2 stroke oil that causes the carbon, Wrong... it's also the additives they put in the fuels today. The carbon inhibitors in 2-stroke oil are there for this reason also. Remember when gasoline used to smell like gasoline, today it smells more like bad cologne. <br />For those guys that like to work the carbon treatment by spraying it down the carbs, Seafoam also comes in spray can called Deep Creep. It's the same stuff under pressure and notes on the can, "Oxygen Sensor Safe". After that, if your engine manufacturer recommends a daily additive treatment then do so. The tank and hose are a one-time purchase and the Seafoam is only costs $5-6.00 per can.
 

Brew2

Chief Petty Officer
Joined
Jan 12, 2004
Messages
427
Re: Is This A Carb Problem?

I agree...sounds like a carb problem. Not familiar with that engine, but if it has a mid-range jet, I'd be checking it. Best thing to do would be a complete cleaning/rebuild of the carbs.<br /><br />Like Bubbacat says, the fuel pump could also be the source of the problem. If carb cleaning doesn't resolve your problem, I'd be looking at the fuel pump next.<br /><br />The decarb is a pretty simple procedure. I'm sure if you do a search on "decarb" you'll have lots of posts to read. Basically, you purchase aerosol can of "decarbing" solution (Sorry can't think of the actual name of the stuff at the moment, but any marine will have it), spray it into the carbs with the motor running, if the motor doesn't stall on its own shut it off and wait (can instructions will tell you how long). Then just start motor and the carbon deposits will be blown out the exhaust. Word of caution...don't have motor facing anything you want to keep clean when you are doing this...those carbon deposits can be a bugger to get off garage doors, driveways, etc.<br /><br />Good luck!
 

crownroyal

Seaman Apprentice
Joined
Mar 2, 2004
Messages
38
Re: Is This A Carb Problem?

Thanks.ill give that decarb a try. I kinda believe 1 of the jets in 1 of the carbs is a little stopped up myself so im going to do another rebuild on them.
 

ob15

Chief Petty Officer
Joined
Jan 4, 2004
Messages
514
Re: Is This A Carb Problem?

That was a great tip! I need to decarb my motor & I think that's the ticket for me. Will propabaly do it this weekend.<br /><br />Man this is a great forum!!!!!!!!!!!!!!!!
 

james roach

Petty Officer 1st Class
Joined
Nov 17, 2002
Messages
216
Re: Is This A Carb Problem?

Sorry to disappoint you but your problem is not carbon related, it's a carb problem. When you pushed in the choke and it took off it is because the choke is bypassing the carb. Dismantling and cleaning out that carb is the only way to fix it. Do a search on carb problems and you will see. Please post your results and good luck.<br />James
 

bubbakat

Captain
Joined
Oct 29, 2002
Messages
3,110
Re: Is This A Carb Problem?

James if you will notice we suggested he do a carb job. The decarb was suggested because of the compression difference on two cylinders.<br />Of course what do I know this is my first rodeo :p :p :rolleyes:
 

crownroyal

Seaman Apprentice
Joined
Mar 2, 2004
Messages
38
Re: Is This A Carb Problem?

Update...I took the carbs off and found a small piece of trash in 1 of the bowls.The carbs were rebuilt not long ago but since i bought 3 new sets i rebuilt them while i had them off. Took it to the lake and ran great. Also did a decarb job while i was at the lake. It seemed like it ran better with more power and low and behold when i got back home and checked the compression the top cylinder that was lower than the lower 2 went up some. Readings are now 120 top and 135 bottom 2.The bottom 2 didnt change any but the top went up 10. Still a difference but hey the motor is 16 yrs old so im happy with it. Thanks people for the help...
 

bubbakat

Captain
Joined
Oct 29, 2002
Messages
3,110
Re: Is This A Carb Problem?

Crown don't you just love it when a good plan comes together. On the two cylinders that are lower take the plugs out and shine you a light in there, if there is still carbon build up just do another decarb. I have had to decarb up to three times before getting them clean.<br /> Now go forth and enjoy that thing for what it was made to do. :D
 
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