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Hunter87
06-26-2012, 9:37 AM
I have a early 70's sea king 5HP, took it out this weekend on my 12' aluminum. It was very dependable but didn't put out at its full potential, above half throttle it just got a little louder and not faster.

I'm hoping someone on here is outboard savvy and can help me out. I run it on 1:32 gas mix as was suggest on another forum. Thanks guys.

P.S. I was fishing and camping at Cherry Lake, with my lack of fishing skills and limited tackle... I managed to catch one 3" Blue Gill!

jmonte35
06-26-2012, 9:44 AM
one of two things.....carb needs to be cleanded/rebuilt or the engine is simply running at full power..you're not going to get much out of a 5 hp motor on 12 ft. boat. I had an old honda that I used to think was the same thing....turned out that was all the little guy had. There was still like a quarter turn on the throttle with very little change. I think the big part of the problem is too much weight to push...it just doesn't have the power to overcome the force of the water in the boat. If you put it on a smaller boat you would probably see a big difference in the RPM output. This is just my experiences.....

the same happens with my new 40 hp 4 stroke Merc. If it's just me in the boat with no gear than it seems like every inch of the throttle is used and continues to go faster. But if I weight it down with 3 guys and gear....there's no difference between half throttle and full throttle......it's just getting bogged down by the weight...

YosemiteSam
06-26-2012, 10:19 AM
I'm going to suggest you look at the carb. This new gasoline with the 10-15% alcohol is bad stuff. In our dirtbikes we have to run the carb bowls dry before storage otherwise the jets get plugged. In our farm equipment we run non-alcohol type gas. It costs about 80 cents a gallon more than premium gas, but worth it to prevent carb problems.

Hunter87
06-26-2012, 10:30 AM
The carb is clean, dismantled and cleaned it myself (kinda scary but once I got in there I saw how simple it was).

I didn't mention that once or twice the exhaust put out some grey/blue smoke, but it didn't last long either time. Also there was a sort of black build up around the ports by the end of the weekend, but I could see liquid coming out of them while running.

Thanks for the suggestions guys, keep 'em coming please.

IVC
06-26-2012, 11:27 AM
...it just got a little louder and not faster.

He, he. Just like my wife when I tell her to hurry up or we'll be late :). If you find a solution, let me know so we can both get rich :).

daveinwoodland
06-26-2012, 11:34 AM
He, he. Just like my wife when I tell her to hurry up or we'll be late :). If you find a solution, let me know so we can both get rich :).
:cheers2::rofl2::rofl2::rofl2:

HokeySon
06-26-2012, 1:01 PM
you are lugging it -- the little beast is trying to work, but it cannot spin the prop up to proper RPMs -- boat is too much for the little guy -- you can try to reprop, but I am not sure it would make a difference on such a small motor (never had one that small, but what you are describing happens on big motors too)

PS: 32:1 is a pretty oil rich mix. Reminds me of the time I had to use straight 30 wt in a jetski to get back to camp: it looked like an old locomotive!

jmonte35
06-26-2012, 2:14 PM
you are lugging it -- the little beast is trying to work, but it cannot spin the prop up to proper RPMs -- boat is too much for the little guy -- you can try to reprop, but I am not sure it would make a difference on such a small motor (never had one that small, but what you are describing happens on big motors too)

PS: 32:1 is a pretty oil rich mix. Reminds me of the time I had to use straight 30 wt in a jetski to get back to camp: it looked like an old locomotive!

Exactly what I thought. Motor sounds fine...little smoke is fine especially on a 2 stroke with 32:1. I don't think its too rich especially for a little older of a motor. That motor just is over worked.....happens all the time to my boat if I put three grown men and duck gear...decoys, dog etc.

dirtracer24
06-26-2012, 8:20 PM
Your definatly overworking the lil fella. Also 32:1 is pretty rich. Ive ran 50:1 in everything from racing dirtbikes to my boat to my weed wacker and chainsaw. Also the engine isn't going to run to its full potential at cherry lakes higher elevation. I think it like 4500 ft there. My 9.9 runs great in the valley but at Lower Bear(also 4500ish ft) it loads up and due to the thinner air up there. As one guy suggested a reprop it might help but I would just look on Craigslist for a bigger motor. Good luck. Btw did you catch anything at cherry lake.

ojisan
06-26-2012, 8:58 PM
A set of new piston rings might work wonders.
Back in the day I had a little 50cc motorcycle.
I rode it everywhere all the time.
Finally, even though it ran perfect, it did not have the ooomph to make it up our slightly-slanted driveway.
Worn out piston rings dropped the compression too low.
A new set of rings made it perform like new.
If those are the original piston rings from 1970, I'd throw a new set in.

Hunter87
06-26-2012, 9:36 PM
Thanks guys, I was going to mess with the oil mix to see what it likes. I lucked out finding this on craigslist for $50 with fuel tank, I don't think I'll be so lucky when I try to go bigger.

I got a huge 3" blue gill! spent more time drinking and trying to boat, plus I'm a very new fisherman. I'll get there, I didn't kill a deer on my first deer hunt either.

weekend_plinker
06-26-2012, 10:27 PM
If you decide to keep on using this motor may I suggest you changing out the water pump impeller. The rubber hardens up and stays bent when this happens the pump does not work