Sea Foam Woes

Discussion in 'Boats and Motors' started by Fish-N-Fool, Jun 2, 2008.

  1. My 70 HP 2-stroke Johnson was running just fine this year. I replaced impeller and have run it a few times since without issue. I thought it would be a good idea to run some Sea Foam through a tank of gas after all the glowing reports on-line.

    I added half a 16 oz. can to 5.5 gallons of gasoline (on the high end of recommended dosage; 16 oz to 10-18 gallons on instructions). I have dual tanks and ran the boat on the straight gas for about 10 minutes then switched to the Sea Foam tank. The motor ran fine on the Sea Foam tank for about 20 minutes at various RPMs. I shut down and fished a spot for about an hour. When I tried to re-start the motor fired up, but seemed to "load up" and it died. A large puff of white smoke (burning carbon I imagine?) appeared. I tried to start several dozen times and it would load up and then die. I switched tanks back to the straight gas hoping to burn out what was in the line.

    I removed the plugs and cleaned - same thing. Removed plugs again and cleaned and was finally able to get the motor running. It did not want to run at idle and wants to shut off if it gets below 1100-1200 rpms. I circled the lake at high rpm hoping to "blow out" anything. It didn't seem work and I had trouble loading.

    I planned on changing out to new plugs and cycling a few gallons of gas through at cruising speed? Also, I'm now gun shy of any fuel additives regardless of all the chatter. Up to this point have never heard anything bad anout Sea Foam, but am convinced it caused the problem - was thinking it broke lose some carbon that may have clogged a jet:confused:

    Any advice would be appreciated - I have a trip scheduled Sunday up at Erie for 4 days and won't go without falwless operation of main motor:mad:
  2. freyedknot

    freyedknot useless poster

    too much sea foam may not be a good thing to run under a heavy load. it will be burning off carbon and most likely will not run well. i would decarbonize the motor and use only 2 ounces to 6 gallons to keep the carbon away.

  3. well your most likly right . you cleaned things up I:D buy a new set of plugs . and dylute that sea foam/gasmix . when you were just siting there fishing it was eating all that nasty stuff up inside your motor .
  4. The sea foam is actually doing its job. It cleaned all that carbon out and in the process fouled your plugs. If it were mine I would go to a lake where I could run it good and hard for an hour. Then put in new plugs and top off the treated tank with new gas. It may seem as it is causing more problems than it is helping but carbon build up is one of the biggest causes of PUKED motors.

    I would also carry a spare set of new plugs in the boat. In case there is still soem residual carbon left to come out.


    that could be part of my problem with my 89 johnson 70 hp i put some seafoam into my tanks and i have only gotten to run it a few times. but i wont know until vics get a chance to look at it.
  6. Thanks, you guys confirmed what I was thinking.

    But it is a harp pill to swallow when you had a perfectly running motor that know runs like crap because of an $8 bottle of fuel additive!! I plan to swap plugs, dilute the mix and run sveral gallons of gas through it. I'll report back with how it all turns out.

    In the future I think I'll stay with the old phrase "If it ain't broke, don't fix it":mad:
  7. don;t blame the sea foam for doing its job, it actualy did a great job ,[next time follow the directions a little better , it;s like good sex;s a little won;t kill you ,but to much just might. lol jim bet the inside of that motor is clean. did what you didto a 90hp johnson . it blew smoke for about a hr ,then ran like new.
  8. If you actually paid $8 for the bottle, I would recommend shopping around a bit. The Speedway stations here in Canton sell the Sea Foam for $5 a can and with gas prices right now...... Just a suggestion. Use it at the right ratio to gas and run it about every 3 or 4 tanks of gas and it will keep that motor nice and clean. It can also be used as a stabilizer over the winter months.
  9. $8.43 with tax from NAPA - they are high on everything in my area, but they are also right on my path home from work - that's worth $3 to me not to have to fight the crowds.

    And as far as the directions go - I DID follow the directions, so perhaps they need to be a little more specific. It says right on the can 16 oz. treats 10-18 gallons. 8 oz to 5.5 gallons is within the recommended mixture.

    We ran approximately this same mixture through an old grain truck with a 400 big block that was running rough 2 years ago. It smoked a little and ran much smoother afterwards (for awhile anyway).

    I'll leave Sea Foam to the rest of you - it won't go back in my outboard ever again.
  10. krustydawg

    krustydawg KrustyDawg

  11. Bassnpro1

    Bassnpro1 OSU outdoorsman

    So this stuff cleans motors up? I have a 7 1/2 hp that is now running like a 5.5 hp. It still starts right up but doesn't seem to have the "umph" it used to. I'm thinking maybe some Sea Foam can cure it?
  12. Lewis


  13. Lewis - have you actually used this procedure or know anybody that has? I've seen this before and was skeptical this would work - wouldn't a mixture that potent completely shut you down??? I have three small outboards I inherited this summer from my uncle when he passed - 1 60's model Johnson and 2 70's Johnsons. I was afraid to try this - not everything you find on internet forums is true!

    I'll admit I am more skepital than many folks & I would like to know "first hand" this works before trying it. I had the mechanic/owner of MP Marine tell me to tear off carb and clean the right way?
  14. freyedknot

    freyedknot useless poster

    i done mine that way last month. it really smooths out the carbs at low idle.
  15. sea foam is a cleaner , not a cure for worn out motors ,a very good product, .
  16. Sorry Fish-N-Fool..... I missed the "half can" in your original post. Don't think I'm the only one that missed that either but maybe.
  17. Lewis


    Yes I have used that method a couple times on small outboards that saw a ton of trolling and it worked great.
    Trolling for hours on end with an outboard at low RPMs does produce a lot of carbon and it needs to be cleaned out to prolong the life of the motor.
    If you dont troll a lot you probably wont ever have to perform the drastic decarb.
    If you do the complete decarb make sure you have a couple sets of spark plugs handy as they will foul.
    Another carbon reducing tip...DO NOT USE CHEAP 2 CYCLE OIL!
    Make sure it is TWC3 rated.
    TWC3 stands for "2 cycle water cooled formula 3"
    The formula 3 has decarbonizing additives.

    Adding SeaFoam to your fuel tank is another story and a very good practice if done regularly.
    Although rare,It could be possible to develop a problem though.
    The cleaner is going to clean the tank and fuel hose also.
    Any debris,gunk or varnish in these could wind up in your carb jets and cause a problem.
    Fouled spark plugs from the carbon coming off the tops of the pistons is another possibility.
  18. Thanks everybody!

    Lewis - I am glad to hear you have done this. My uncle took much better care of his things than most people (including me). These motors sat for a few years as his health failed, but all three started and ran. I putt new points in the 7.5 HP and it runs like a champ. However, the 5.5 HP motor was used exclusively to troll on his boat and it runs very rough at low idle. It runs good once you open it up. I think I will try this and see how it does. I do run the manufacturer's recommended oil in all my motors.

    Snobal - no big deal. It just ticks you off when you think you have done something unnecessary and now your perfectly running motor runs like a turd!
  19. UFM82

    UFM82 The one others want to be

    The Sea Foam is breaking up the carbon in the engine- from the ring lands, the piston tops, etc. Yet somehow that same carbon is sticking to a plug and fouling it? Does that make sense? Actually I would believe that the SeaFoam is actually cleaning your plugs at the same time that it is cleaning your engine.

    Carbon only forms when the fuel is burnt. It does NOT form in your fuel lines, your carb or in the jets. It's in the areas that are exposed to exhaust gasses

    Additionally, if the plugs DO foul for some reason, why on earth would you replace them? Do you throw away a glass because you got water in it? Do you throw away your kitchen table because you spilled ketchup on it? So why change plugs when you get fuel on them? Wipe them off! Clean 'em with a rag or a little cleaner. It's just fuel guys. Unless a plug is actually physically damaged or severely deposited, there is no reason to replace a fouled plug. You're just tossing money overboard.

    Follow the link for the decarbing posted by Dunk and do the process exactly. It works just fine and does a great job. I've done it on more than one engine including my own EFI.


    It's probably just your fuel bulb.