'74 20hp Merc 200, what to check for & general guidelines for first startup

[treebound]

Hi,
Just got a boat/motor/trailer from some friends and have some questions and want someone to look over my virtual shoulder to check my thinking. Questions are numbered to help keep track of my tendancy to meander and use too many words when typing.

I checked the serial number and found a web reference that the outboard is a 1974 model.


It has been sitting in a barn for several years, and the last time they had it out he had trouble getting it started due to his weak shoulder but not sure if there were ingition issues as well.

It was about 20degF in the barn, but I did manage to pull the starter rope and felt compression in both cylinders. But due to the temp and the engine sitting for several years (2-3 maybe) I know it would be stiff just from that.

I have no idea if he emptied the carb or checked the lower unit fluid before parking the boat in the barn.

Right now I have the outboard laying on the garage floor off of the boat and I would like to find or buy or rig up an outboard stand before I do too much with it.

My thinking/plan/questions:

1. What is the gas/oil ratio supposed to be? I assume 50:1 but want to confirm that.

2. I plan to check the lube in the lower unit to check for moisture and ensure that there is something in there.

3. I will pull the plugs and check for spark and do a thumb-over-the-plug-hole to check for basic compression.

4. I plan to poke around the water drain hole to check if any mud wasps or other critters have build nests in there.

5. I may or may not get a carb rebuild kit, but initially I think I'm just going to see if it will run before spending any money on it.

6. The flipper lever on the side of the cowling, I assume that is forward/neutral/reverse, and I assume I want to initially start the outboard in neutral, and I probably want it idling before putting it into gear or when switching directions, correct on any of that?

7. Can I just slip this into neutral before the engine idles down? Or should I want until it fully idles down? I'm thinking of times where I might hit bottom or run into weeds.

8. They also gave use two spare dinged up props and said something about rubber between the shaft and propeller body to help avoid breaking a shaft if the prop hits a rock or something. Is there a way to check the spare props or the one on the engine to see if the rubber interface is still good or not?

I don't have a manual for the engine (yet), but have messed around with engines and a few outboards in the past, so anything I end up doing to this will probably be done at home.

Thanks in advance for any comments or answers.

Here is a pic of the engine before I removed it from the boat:

 

[Flipperboat]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

I purchased an engine much like the one you are talking about in your post. Here is what I think about it. Make sure before you spend the first dime that you survey everything it will need because the price of repair can be costly. I bought a 1972 which was the only year for that ignition system and the parts are hard to find and pricy. The wiring on your model is very poor. I would look up worst case scenario just so you know how much it will cost. I believe they change the ignition system for your year model to a trigger, stator, and switch box. The switch box being the most expensive item. Also if you are handy make sure the lower unit will separate (3 bolts and one under the zink) to see if you will need a water pump as well. Replacement carbs or a carb cleaning is easy and basic. All of these things add up and I still don't have a running 20HP. I should have surveyed mine first but like a fool started replacing ignition parts that were bad and replacing bad wires. All I'm saying is for the money you put into a non running 20HP you could sell yours and use the money on a down payment on a newer 20HP 4stoke that won't leave you stranded. I was trying to restore mine for nostalgic reasons to match the year of my rare find boat. I have seen non running 20HP engines sell as high as $200 on EBay. Hope this helps.

 

[treebound]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

Thanks for the reply, that does help with my thinking and plans. I'm also thinking of getting a smaller kicker motor (1hp-6hp) to use as a trolling motor and an emergency get back to the dock option. Newer 4-strokes are beyond the budget at this time, but that would be ideal since I don't need nor want to stay period-correct with the boat.

We're thinking of heading up to a lake this year which is a bit over 1 mile wide and 7 miles long, that would be a long row if the engine dies.

 

[Silvertip]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

The engine needs to be in neutral to start it. It also needs to be at idle before it can be shifted. You cannot likely shift into neutral if the engine is NOT idling due to the loading on the clutch dogs. If you are "checking" the lower unit lube, why not just drain it and refill with fresh lube. Looking at the plugs is the same logic. You have them out -- why not replace them. Two of them will only set you back a couple of bucks. Checking for spark is more productive than checking compression at this point. Compression does you no good if there is no spark to light the fire. Fresh fuel, new fuel filter, checking the primer bulb and fuel hose and replacing those if necessary is in order. As for a kicker for trolling, that 20HP will troll all day with no issues and you eliminate the weight, trouble, and cost of another engine.

 

[treebound]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

Thanks for the input, will take note. My plan right now is to figure out what works before dumping any money into it, but yeah sparkplugs and gear lube are relatively cheap.

My spare smaller outboard plan is from my having grown up on the west coast near Seattle where winds and tides can quickly get you into trouble if the engine dies or won't start while messing around in Puget Sound. And while tides are not a factor here in Wisconsin, winds and big water are and I might want to sneak out onto Lake Michigan with it on calmer days. Not sure how comfortable I am with 39 year old electrical components on the engine, probably okay if they still work but still don't want to get stuck if they fail.

Anyway, thanks for the input and thoughts, will definitely keep that all in mind.

 

[quicktach]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

1) 50:1 2) Drain & refill with fresh gear oil. Drain oil over a magnet to look for signs of gear wear 3) put in new plugs to check for spark 4) a compression gauge is a cheap investment if you're going to work with motors going forward 5) Agreed 6) Yes ...but don't run it without being in water or with muffs on the intake ..or you risk wrecking water pump 7) Shift on idle 8) Difficult. You can put engine in gear ( but turned off ) and try to move prop by hand ...better to test in a shop though 9) Invest in Merc manual. Seldoc not bad but Mercury Marine better 10) remove cowl and look carefully at wires for signs of cracks, chipped insulation, overheating. When you drain gear oil ...if it's milky you've got a water leak into lower unit....11) with plugs out, peek into combustion chamber with a pencil trouble light to look for scoring on cylinder walls and look for carbon build up on piston top ....

 

[treebound]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

Perfect, thank you. I'll post an update of what I find when I start working on it.

 

[treebound]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

Okay, while pumping water out of the garage (rain + snow melt = water in the garage) I started working on the outboard.

Got the cover off and while figuring out what size spark plug wrench to use I found that the plugs were barely finger tight. I have no idea if that is why it stopped running for the previous owner, or if he had taken them out trying to figure out why the engine wouldn't start and then maybe just put them back in finger tight.

Anyway, I tried to rig up a ground to the spark plug threads and then to a grounding point and gave the engine a few pulls on the starter cord to see if I could get any spark. Even with the lights out I could not detect any spark. I don't know how fast I have to pull the cord to generate a spark, it's possible I wasn't pulling fast enough if there is a minimum rpm to generate the electrical juice enough to fire the plugs. I don't have a service manual yet and none of the on-line links I've found so far seem correct for this engine.

I did peek into the cylinders with a flashlight and everything looks fine, what I could see of the cylinder walls looked good and un-scuffed.

I did find one screw laying inside the lower cowling on the port side (left side facing the bow of a boat from the stern, ? ), maybe an inch long phillips head machine screw x maybe a 1/4" shank size. I couldn't see anyplace obvious where it might have fallen out of, but it did look like it could have come from the outboard.

I didn't look that close at the wiring yet.

The throttle initially would not rotate more than a quarter turn, but after I kept playing with it it finally opened up all the way and now rotates for the full range. I'm thinking something was just gunked/dried up, which indicates that I'll probably have to pull the carb and clean it out, which I don't want to do until I know if I have spark or not.

I didn't write down the plug numbers, but from some random web place that I neglected to bookmark but did write down the info from showed the plugs as Champion CHA833 L78V, is this correct for this engine? Is there a way to check the voltage from the plug wires without buying new plugs and without frying a multimeter or zapping myself? This then brings me back to how fast or slow I need to crank/pull the engine over to generate spark voltage.

Thanks for any additional info. I'll be searching again today for a manual or at least one on-line where I can get info from.

edit: found the manual link under the slider bar at http://boatinfo.no/lib/library.html

 

[treebound]

Re: '74 20hp Merc 200, what to check for & general guidelines for first startup

woohoo, got some spark. Don't know if it just needed to be spun a few extra times or if I had the plugs grounded better, but I was able to get both plugs to spark a few times. The existing plugs are NGK BUHW-2 so I'll have to see if they cross to the Champions and will try to find a local store with plugs in stock.

Wiring looks okay, maybe just a little wet looking from gas/oil residue. I still can't find where the loose screw came from though.

I'm going to check at the library to see if they have or can inter-library loan a service manual. In any case I'm happy it had spark.