TOPIC: 66 Larson Help

My Grandfather gave me this boat and I would like to put it back into the water. It is a 1966 All American Larson, 1959 (??) 90 HP Envirude on the back. It has been sitting up in the boathouse for well over 15 years. I would like to get it fix but do not even know the first thing about how to get this thing running. I imagine all of the lines, hoses, etc.. are dry rotted and I remember the boat was put away not working so I don't think the engine would even work. The boat is located in Northeastern PA. Any info would help

Wow! that looks really great! You've definitely found THE best source on the 'net for help. There may not be as much to do as you think but you will have some things to attend to. It's not that hard and many if not all of the parts can still be found. I know others will respond with recommendations and sources, etc!

Obviously kept in a garage this whole time! Lucky you!

First, make sure the motor can turn. That the flywheel can rotate.
If there isn't any clunking or banging continue.

It is always best to test motors in water. The rubber water pump can be damaged by running dry even for a "test fire". Whether it is a garbage can or a lake is up to you. (no propeller in the garbage can. Leave it in neutral)

At this point I would try some 50:1 or 24:1 (whatever the motor says) fuel and cranking. (others may disagree) I don't like to take stuff all apart first. If it works the way it is, I just use it that way.

If it happens to start and run, then you should change the lower unit grease/oil right away before you drive the boat.

If it doesn't run, check the plugs for spark. If they spark, then likely the carb is gummed up with dried oil/fuel residue and will need to be cleaned out. I like to take the carburetor apart and clean it out. I don't like to get carb cleaner near 2 cycle engines because if it gets in the cylinders it can cause places where there is no oil and score the cylinder wall.

Good luck. Have fun.

Getting the "Boat" ready- appears to be a non-issue. It appears in great condition. I would look over the bottom of the hull for cracks or impact damage. Then I would inspect the transom. Grab the motor leg and push and pull on it- to see if the transom twists or is solid. It's hard to tell someone how to do the "rap-test" and listen to tell if the transom is solid.. It's a pretty subjective sound. But you can use a rubber mallet. A good transom will "bounce" the mallet , while a rotten transom will not recoil much and you'll only hear a dull thump.

Engine:
1) Mix up some gas/2-stroke oil @ 24:1 ratio in a spray-bottle.
2) Pull all (4) spark-plugs and spray some of the fuel/oil mix into the cylinders.
3) With the plugs out- test to see if you can turn the flywheel over by hand (clockwise ONLY!) If it turns, move on. If not, you will need further assistance in "breaking" it free.
4) Place the lower unit in a garbage can/barrel of water until above the extension housing. This is to lubricate and prime the water pump while doing the other tests.
5) Leave the plugs out- and have someone crank the engine with the starter. While he/she/it cranks... spray some of your fuel/oil mixture into the carb. Crank a few times in 10-second intervals. Spray only while cranking. Watch for fuel-mix out of the plug-holes.
6) If you have a compression tester- use it. Write down what each cylinder reads (should be 85-100 psi on a "dry" motor). If you don't have a tester- you can use your finger. Each cylinder should have enough pressure to "blow" your finger away from the hole. You will know if you have a "down" cylinder.
7) Now you can check for spark. Remove the distributor cap and check the points for corrosion. If there is any- you will need a point-file or emory-board to clean then. No rougher than 180G sandpaper will do in a pinch.
8) I find the easiest way is to install each plug- one at a time- and attach an inductive timing-light to the plug wire. The light will flash if you have spark. It won't tell you the condition of the spark, but it beats trying to hold a plug against the block, or making a spark-tester.

The above tests will get you to the point of knowing if you have a motor that "CAN" run.. Let us know how the testing goes.

The motor is definitely newer than 59. My guess would be it's about the same age as the boat.

Doug Reeve wrote:

The motor is definitely newer than 59. My guess would be it's about the same age as the boat.

Yes, It is a 1966 100-S with electric shift.

www.old-omc.de/e_1966/seite_04_05.jpg

69fabuglas is right. When a motor has been sitting that long it is best to get some fuel/lube mixture into the whole motor before cranking.