Trouble shooting dingy motor

[Tom1340]

My 1983 suzuki outboard (9.9 hp 2 cycle) suddenly stopped reaching full power. It starts on first pull, idles great, accelerates okay up to a point, then just kind of stabilizes well short of normal speed, running slightly erratic. The two year old plugs were really black with chunky soot, so I changed them. Also pulled carburetor and inspected float and needle valve...very clean.
My next uninformed guess is the coil is weak, and failing under heavy load. So I will try to find a replacement here in the keys, before we head to Bahamas.
In meantime, if anyone has any guidance, please let me know.
Thanks, Tom

[a64pilot]

Coil is possible, but does this carb have a choke or an enriching circuit. If it has the enriching circuit, that is another possibility. Good you pulled the plug, that way you know it's not going lean, which I would have guessed was the case and a plugged high speed circuit.



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[Reefmagnet]

Assuming you've already tried with a fresh fuel/oil mix, a twin cylinder 2 stroke outboard can start and run at low speeds remarkably well with one cylinder not firing at all. It just won't reach anywhere near full power and run like junk at the higher end. Pull one lead, start and run and then repeat for the other cylinder, swap plugs etc to test for plug / coil failures

[Vasco]

Just fixed two yamahas with similar problems. 90 percent of the time it's the carb. Remove and clean! Especially the jets.


Toronto in summer, Bahamas in winter.

[Tom1340]

Thank you all for your comments. I hope it is a dirty carb problem, and I will go through it more thoroughly and clean the jets. Finding new coil and CDI for this vintage motor is proving a challenge.

[delmarrey]

Originally Posted by Vasco

Just fixed two yamahas with similar problems. 90 percent of the time it's the carb. Remove and clean! Especially the jets.


Toronto in summer, Bahamas in winter.

Ditto!
Pull the jet out of the carb and see how the metering hole looks. If its been sitting for a long time with new fuel (10% alcohol), it retains moisture and the jet clogs up with oxides.

Now days, I run my fuel systems dry for storage.

[Ex-Calif]

I don't have anything useful to add except - 32 year old outboard? Wow!

Has it ever been overhauled?

[Vasco]

If you do decide on a new outboard wait till you get to the Bahamas and get another two stroke. Yamaha 15, the cruisers choice


Toronto in summer, Bahamas in winter.

[Cadence]

Originally Posted by Ex-Calif

I don't have anything useful to add except - 32 year old outboard? Wow!

Has it ever been overhauled?

I had the question on the age and maybe time to replace it.

Knowing nothing about that engine, at that age does it have points? If so, I had two OMC 9.9hps. that exhibited that symptom. The first one drove me crazier thinking the points where not holding a gap. Ended up being a shot upper main bearing. Time to become the proverbial boat anchor.

Good luck.

[Scout 30]

Go to Boats.net. They sell parts for your motor. I've bought Honda parts from them & they are good people to work with. If you are using gas with ethanol in it that's probably your problem. Replace the jets.


1983 DT9.9ELD Suzuki Marine Outboard Carburetor Diagram and Parts

[anacapaisland42]

Several people have commented but it should be emphasised:

if you are using gas with ethanol you should run dry.

Preferably use premium, no ethanol, gas

Bill

[Tom1340]

This motor has run like a charm until this week. It is clean as a new whistle and starts on first pull every time. I don't think its ever had ethanol in it. BUT that's history. The jets are clean and the motor won't reach speed. It will cost me a week and about $300 to find out if the problem is the CDI unit. I think it's time for a new motor.
Vasco, getting a new 2 cycle Yamaha in Bahamas is very appealing. But I hate to get there to find out none is available. Do you know who sells them? If so, I will check availability before heading over.
Thanks to all who've offered comments.
Tom

[belizesailor]

Originally Posted by Tom1340

This motor has run like a charm until this week. It is clean as a new whistle and starts on first pull every time. I don't think its ever had ethanol in it. BUT that's history. The jets are clean and the motor won't reach speed. It will cost me a week and about $300 to find out if the problem is the CDI unit. I think it's time for a new motor.
Vasco, getting a new 2 cycle Yamaha in Bahamas is very appealing. But I hate to get there to find out none is available. Do you know who sells them? If so, I will check availability before heading over.
Thanks to all who've offered comments.
Tom

Why not just replace the CDI? Easy & inexpensive on most motors. Recently bought a new one for a Johson 15 for $45.

Then if you get to the Bahamas and don't find what you want you've got a good motor until you do.

And you get to retain the prize for oldest outboard in the anchorage! ;-)

[sailorboy1]

"Trouble shooting dingy motor"

I was expecting a gun thread, but not saying that isn't the answer.

[Cheechako]

I've had your problem twice.
1) the rubber hub in t he prop was "spun"... so it wouldnt grip after I got to a higher rpm.
2) the main bearings were shot and had to be replaced.


Hopefully yours is not #2... although I had help and did it cheap like $15parts