No zip in 200HP('86)? Sea Foam help?

[keegan99usa]

Ok, long story short. boat ('72 Hydrodyne 18') and motor not used since 2003. Boat needed a new transom, etc.... Anyways, got the engine running again and on the boat which used to shoot out of the water and top off about 60 MPH. Now it goes maybe 35 and no zip at all. it runs smooth, but not strong. Cables are "tight", but I remember this boat just flying with this engine. I had a recommendation of using Sea Foam fuel additive to get the gunk out as a remedy to cleam the varnished carbs. Good idea? Bad Idea? Any help appreciated. BTW, gaskets on head were replaced (one was leaking ) and compression showed all about 110, one cylinder at 105, so all is good there?
Thanks
Keegan

[robert graham]

sounds like a sure bet that the carbs need to be cleaned and set, probably gunked up from sitting for several years. then use the Seafoam or Stabil and the Ringfree all the time with a fuel/water seperator (Walmart $25) and you should be good to go. Good luck!

[Hamfisted]

At least clean out the jets...

If you're comfortable rebuilding carbs that's the way to go, but short of that you need to at least remove and clean out the jets in the carb bowls. The small brass one is the idle jet, the bigger one is the main jet. On the main jet you will find an orange O-ring, make sure that O-ring is not torn or distorted or you will get carb flooding. The small idle jet has tiny orifice holes in the sides, make sure they are cleaned out. Spray carb cleaner into every orifice, and you should get a reactionary spray downstream as it exits the passage. Spray up into the holes where you removed the jets, make sure the junk in the bowls flushes out. For carb cleaner I recommend either Amsoil PowerFoam (the best) or Berryman's Chemtool Spray ( Walmart ). You can try a shock treatment of SeaFoam (fill the Racor filter with straight Seafoam...) and see if you can free up any carbon that's stuck in the motor. But cleaning out the carbs and a fresh set of plugs is your best bet.



- Mike

[keegan99usa]

Thanks for the help. I'm really not a motor guru, but am very mechanical. Not sure what the Racor filter is though. I did put some new plugs in it, have not run it yet, but i would think a good carb cleaning is in order.
Thanks
Keegan

[keegan99usa]

Just another note: If there is carbon and junkin the carbs and jets, and I get that cleaned out, will this thing likely run like a champ again?

[robert graham]

get the carbs cleaned and set and it'll run like a top. then use Stabil or Seafoam and Yamaha Ringfree all the time as instructed on the bottles, add a fuel/water seperator(Walmart $25) and you'll eliminate about 99% of all your fuel related problems. this works because my motor is a 1999 and i've never had the carbs cleaned or adjusted...just runs like a top all the time! this preventive maintenance is really no big deal at all after you establish what you need to do and it's so worth it to have your motor run right on the water!

[keegan99usa]

Thanks Robert!

When you say "set", what are you referring too?

[robert graham]

after cleaning,there are air/fuel mixture jet adjustments, float levels, throttle adjustments and sychronizations so each carb and cylinder will breath just the same. that requires special equipment and knowledge, so I would just pay a professional with the experience to "do it right", especially on a multi-carb/cylinder engine. If you get your preventive maintenance down right then you probably won't need to take your boat/motor in "to the shop" very often. I bought my motor new in 1999 and had it to the shop once for a new impeller. I might have been able to do that myself but it would have been a learning experience and i know there are little tricks to every job and so I paid the guy $130 to do it right. I'm still running the original spark plugs, just sand blast the carbon off a couple of times a year and they look like new! Just keep your fuel clean, fresh, stabilized, filtered and you'll be ready to go! Good luck!