School a newbie on outboard maintenance

F470 · 01 October 2013, 00:22

I recently bought a 1980 Suzuki DT-40 40hp 2-stroke outboard. It started up first try when I inspected it but when I attempted to start it yesterday it started briefly twice but died. It had been sitting out in the rain for several days and some moisture may have made in under the hood. It's also possible that the newbie outboard owner flooded it. Any suggestions for what to do, how to get it started? I am also looking for maintenance advice. It appears in great shape but no record of any kind of maintenance exists. Advice appreciated.

captnjack · 01 October 2013, 00:44

To start...
How old is the gas in the tank? How about the gas in the carbs, is that older than a year?
Squirting starter fluid in the air intake manifold can you get it running?

Sitting, upright on a stand or transom in the rain is no big deal.

F470 · 01 October 2013, 01:03

Brand new tank and fuel hoses. Will try starter fluid.

95gstnj · 01 October 2013, 01:18

Older 2 strokes are great. Very simple to operate and maintain. Once you get the basics down, they are all pretty much the same. They will last forever if you maintain it. When troubleshooting, basically look for compression, fuel, and spark. That's all they need to run.

A good list of stuff to change out is:

Waterpump every year, spark plugs every season or every 100 hrs, lower unit oil every 50 hours or so, and seafoam or decarb every 50 hours.

If it sits for a while, you might have to take the carb off and clean it out.

That's basically it.

Don't overdo it with the starter fluid. If it runs with a couple second burst from the starter fluid, it's probably fine and just needs the carb cleaned out.

F470 · 01 October 2013, 01:22

Great advice. Thanks! How do I clean the carb? What is sea foam/decarb?

sailit · 01 October 2013, 01:27

DONT EVER USE STARTER FLUID ON A 2-STROKE ENGINE it has no oil in it and the cold start up with no oil could scratch the cylinder..

F470 · 01 October 2013, 01:28

Wow. ok. No harm done yet as i haven't tried started fluid yet. I'm looking to try some decarbonizer fluid though.

95gstnj · 01 October 2013, 01:32

Look at YouTube videos on cleaning the carb. They are all mostly the same. Take it off, open it up - be nice to the gaskets if you're gonna reuse them. Then spray it all liberally with carb cleaner to get the gunk and varnish out. The important part is to get the jets COMPLETELY clean so fuel flows through them freely. And to adjust the float correctly. It'll take you an hour or so the first time.

Seafoam is very important for 2 strokes since they build up carbon quickly. You put it into the fuel and it breaks up carbon deposits. Take a can of seafoam and mix it with 3/4 of a gallon of gas or 50:1 if you mix. Run that through the motor. It will smoke like hell and might sputter or die. Turn it off let it sit for 15 mins then run regular gas through the motor. Take it for a spin until it stops smoking more than usual. All done.

If you do it in a test tank you'll see all the crud that came out of the motor.

95gstnj · 01 October 2013, 01:34

Yea, starter fluid doesn't have lubricity so really don't use much. Just a second or two of spray to see if it turns over won't hurt. The other option is to put gas and oil at 50:1 in a spray bottle and use that instead of starter fluid

F470 · 01 October 2013, 01:35

Sea Foam has many products. Which one mixes in the fuel?

How do I adjust the float?

95gstnj · 01 October 2013, 01:39

Standard can you can find at walmart or any auto parts store for $9. White with red lettering says seafoam.

Float should be parallel with the body of the carb when you hold it upside down. When the carb is all clean blow through the fuel intake of it. You should get airflow. If you then flip the carb upside down, the float should rise and now you can't blow air through it. Just a trick to check if the float works.

95gstnj · 01 October 2013, 01:40

Seafoam

F470 · 01 October 2013, 01:41

This one?

I like to ask questions.

Thanks for all your help so far. Sounds like a tune up is in order!

95gstnj · 01 October 2013, 01:43

Yep that's it. No prob. Once you get a good understanding of kinda how things go on a 2stroke, they are all basically the same all the way up through big 250hp outboards.

95gstnj · 01 October 2013, 01:45

Also, once you do seafoam it, take it easy for the next few hours until it gets a little carbon built up. Easier to scratch a piston when it's completely clean. Just don't beat on it WOT for an hour or so.

F470 · 02 October 2013, 00:16

If I decide to change the lower unit oil, what type of gear oil should be used for a Suzuki DT40? The manual calls for Suzuki outboard gear oil or SAE 90 hypoid gear oil.

F470 · 02 October 2013, 02:03

I was also going to replace the Fuel filter but it does not appear to be replaceable. Looks like you just soak it in solvent?

captnjack · 02 October 2013, 16:26

Quote:

Originally Posted by sailit

DONT EVER USE STARTER FLUID ON A 2-STROKE ENGINE it has no oil in it and the cold start up with no oil could scratch the cylinder..

Ummm there's gas and oil in there too (possibly too much). A 2 second spray of starter fluid into a 2 stroke air intake isn't going to hurt anything.

captnjack · 02 October 2013, 16:29

Quote:

Originally Posted by F470

I was also going to replace the Fuel filter but it does not appear to be replaceable. Looks like you just soak it in solvent?

SAE90 gear oil sold by marine stores everywhere.

The onboard (under the cowl) fuel filters are typically disposable plastic units which are replaced. Get a proper fuel water seperating fuel filter for the transom to supplement it though.

jyasaki · 02 October 2013, 17:09

Quote:

Originally Posted by F470

If I decide to change the lower unit oil, what type of gear oil should be used for a Suzuki DT40? The manual calls for Suzuki outboard gear oil or SAE 90 hypoid gear oil.

I think you just answered your own question.

BTW, if the rainwater is the cause of your non-starting, I would NOT take the thing out on the water. Outboards are meant to be used in a wet environment; if it doesn't work when damp, it's not reliable enough to run with.

jky