Re: 77 140 Unusual Engine RPM
Yeah I kinda figured that it must have taken the gum out of something and brought the engine rpm up. This is the process I used, I can not take credit for this writeup, i found it on here, I can not recall who wrote it, I just put it in a word format and numbered the steps to make it easier to follow for my own use. It defiantly took a lot of crap out of my engine, i think the last part was the most useful, that deep creep is some good stuff. I am surprised however that I didn't get the fire dept called on me, i am sure my neighbors were pissed.
De-Carb Process
This works for Carbed, EFI, Ficht, HPDI, Opti-max and even 4-strokes... and should be administered after every 50-60 hours of use.
1. 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. 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.
2. 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.
3. 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.
4. If your engine has a fuel plug then you will also need a fuel plug on the smaller tank's hose.
5. 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.
6. Then shut it down and let it sit for another 15 minutes.
7. 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. I've never seen one still smoke after three doses.
8. 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.
9. 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.
10. Decarbing is a 2 part process. The first part is preventative, done by using a fuel additive to prevent carbon build up. SeaFoam is one such fuel additive and can be found at most auto parts stores. It also works as a fuel system cleaner and should be used as a preventative maintenance procedure.
11. If Your intent is to REMOVE the existing carbon buildup from the cylinders, heads, and rings, a spray decarb solvent product, such as SeaFoam Deep Creep, Power Tune, or Ring Free, is needed to do the decarb process. Free moving rings are what seals your cylinders and gives you compression. Compressed and stuck rings means loss of compression, broken rings, damaged pistons and heads, and eventually, engine failure.
12. Run engine at fast idle, with engine running and warm,
13. Slowly spray liberal amount into each carb. Its gonna smoke up the place.
14. Spray for a couple minutes,
15. Now spray a larger amount into the carb(s) until engine chokes out and stops.
16. Remove spark plugs and spray the decarb product liberally into each cylinder,
17. Install the spark plugs, let it soak for an hour or more.
18. Start the engine and run at medium throttle, or if at the lake, run it at full throttle. It won't hurt to spray some more through the carbs.
19. Run it for atleast 10 minutes to flush the crud out of your engine.
20. Now remove and clean, or replace the spark plugs.
21. It works well to do the spraying, the night before you go to the lake. This way you can let it soak overnight, and run at full throttle at the lake. Don't do this in front of the garage door or the house, unless you want it covered with greasy black crud.
