Trouble shooting dingy motor

[MBWhite]

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

A simple way of troubleshooting your issues here is to first take the dinghy out for a run and give it a shot of starting fluid while running with it wide open. If it takes off then you can look into the fuel system, though things like poor spark or low compression can also be compensated for with starting fluid. Also, just give it brief squirts and not a steady stream for very long. If you have or can borrow a timing light, clip it on the leads and just look at the quality of the light flash, if the CDI is failing you'll get a very erratic flash and not a consistent, even strobe effect. Stick a piece of tape or make a mark on the flywheel if you want, it is a little more precise to watch the timing mark jump around but to be honest, when ignition components start failing it is usually visually obvious by looking at the rhythm of the flashes.

Next couple of items to inspect before you spend money: Your fuel tank and line, Disconnect the line at the carb and make sure the fuel runs through unobstructed. If an external tank, usually you can hold the end fitting open with a small screwdriver and give the squeeze bulb a couple squeezes and collect the fuel in a container, look for water or debris.

Next on the list is to do a compression test, poor running and sooting can be caused by low compression.

Finally, after you've done all of that I'd suggest purchasing a new set of plugs and seeing what effect that has. It could simply be that carbon fouling has ruined your plugs even with cleaning, but it is not that common which is I don't suggest immediately running out and buying new plugs before you make the other tests first.

Good luck!

[a64pilot]

I sure wouldn't toss it, I have a 25 HP Mariner (really a Yamaha, I think) older than that and it runs beautifully, condemned by PO, once I replaced the missing parts in the enriching circuit, it ran beautifully.
New 15 HP two smoke in Bahamas is what guys, >$2K ?
Great motor, but so is yours I bet

[a64pilot]

Originally Posted by Tom1340

My 1983 suzuki outboard (9.9 hp 2 cycle) suddenly stopped reaching full power. It starts on first pull, idles great,

Can't be much wrong, never seen a worn out motor start on first pull and idle great, most new motors won't do that

[Vasco]

Harbourside marine. Nassau
Hbsmarine.com


Toronto in summer, Bahamas in winter.

[Tom1340]

I believe I have ruled out fuel problems, so that leaves electric. If I can find a good mechanic in key largo, or find an induction timing light, I will investigate further. But the suzuki dealer in key largo won't even look at my engine cause his mechanics don't understand the old technology. The cost to buy a new CDI from boats.net is $300. I fear I may be missing something simple on my engine, but I'm planning on a new engine.
Harbour side marine in Nassau offers an 8 hp Yamaha enduro that sound like a good fit. (Vasco, the 15 hp is almost twice the rated power of my air floor dinghy, and it's weight is more than I can safely manhandle. Hopefully the 8'hp model proves as reliable).
I appreciate all your comments.
Tom

[belizesailor]

Originally Posted by 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

Trouble is that in many venues you don't know...you just take whatever is in the barrel or you don't get any.

And, running till the motor dies does not remove all fuel from the carb. I do that regardless, and still often end up cleaning the carb. I have seriously considered cleaning the carb before storage to be sure and eliminate the issue.

[Scout 30]

Originally Posted by Tom1340

I believe I have ruled out fuel problems, so that leaves electric. If I can find a good mechanic in key largo, or find an induction timing light, I will investigate further. But the suzuki dealer in key largo won't even look at my engine cause his mechanics don't understand the old technology. The cost to buy a new CDI from boats.net is $300. I fear I may be missing something simple on my engine, but I'm planning on a new engine.
Harbour side marine in Nassau offers an 8 hp Yamaha enduro that sound like a good fit. (Vasco, the 15 hp is almost twice the rated power of my air floor dinghy, and it's weight is more than I can safely manhandle. Hopefully the 8'hp model proves as reliable).
I appreciate all your comments.
Tom

These days with the crappy gas we're dealing with the only way to rule out fuel problems is to replace the carburetor. I had a 25hp Honda that did exactly what your motors doing & it was the carbs. That was an expensive lesson.

[Scout 30]

Originally Posted by belizesailor

Trouble is that in many venues you don't know...you just take whatever is in the barrel or you don't get any.

And, running till the motor dies does not remove all fuel from the carb. I do that regardless, and still often end up cleaning the carb. I have seriously considered cleaning the carb before storage to be sure and eliminate the issue.

Use only non ethanol gas, add stabil, run the carburetor dry when you're done running the motor, store it with a full tank & the vent closed & there's still no guarantee you won't have a problem.

[markpierce]

Shoot. What do you expect from a dingy outboard motor missing a consonant? Definitely, not warranted to power a dinghy.

[Custom30]

Originally Posted by belizesailor

Trouble is that in many venues you don't know...you just take whatever is in the barrel or you don't get any.

It is easy to test the gas wherever you are for ethanol before buying a large quantity of it. It requires you to purchase a small amount to test. The only other things you need are a clear glass container and a means of making a temporary mark.

Put the few ounces purchased in the container and mark the level carefully. The next morning check the level. If it has increased, the gas has ethanol. By proportion the ethanol will absorb moisture from the air (just like it does in your engine) and increase in volume.

And, running till the motor dies does not remove all fuel from the carb. I do that regardless, and still often end up cleaning the carb. I have seriously considered cleaning the carb before storage to be sure and eliminate the issue.

Draining the bowl would come close, but who's going to do that every time?

By the way, I've found the best carb jet cleaning tool set. Ask a friend who plays guitar for a used set of strings, unless of course you play guitar yourself. Cut each string off about 1 1/2" on the ball end, and voila! you have a graduated set of reamers perfect for carb cleaning. Start with the smallest one, with cleaner ,and work your way up till it's clean. If you don't play or know someone who does, just check out the guy or gal making a living with their guitar at the local tiki bar. I'd bet they'll have a couple of used sets with them just in case. I generate about 100 sets a year. Hey maybe I should sell them on Ebay as carb jet cleaning kits!


'

[gah964]

first check fuel
2-check carb jet let set over night in THE GOOD STUFF AT auto parts
3-check compression compression under 90 no good
4-check spark and plugs
5-if bad compression check for a stuck valve.
6-if no spark clean up fly wheel
7-still no spark check points if you have points
8-check or replace coil and boot
9-capacitor
10-CDI