1974 Johnson 6HP model 6R74C

OK, Here the scoop:
I just purchased a 1974 Johnson 6HP model 6R74C. I would say on the outside it looks fair to good. Inside looks very clean. I filled up a barrel with water, mounted it, bought a new 6 gal tank, fittings, hose etc. Put 2 gallons of gas with a 50:1 mix, ( 6oz. oil with 2 gal gas. It has not been run in 2 years. The old man told me it ran sweet the last time it used it. He has been disable for 2 yr and stored it in his shop. I gave him $300 for it. I pulled my arm off and finally it started. Lots and lots of smoke. It ran a few minutes, plenty of water coming out from the exhause. Ran a little rough and finally died. Sat there a few minutes and cranked back up, ran a little longer and died. I had to let it sit a lil bit and it cranked again. Shifted fine. Cranked it again this morning, seem to run a lil longer but finally died. Thats the way it does. Runs a lil bit and dies, but will crank back up. Runs better half thottle. Slow it down and it dies, run it too high it dies and it will die after about 4 minutes midrange. Cleaned the plugs but nothing else. Should I invest more or get rid of it? I have a 14ft shallow aluminum boat for it and will use it in small lakes and creeks. I have a 15" transom and I think the motor is also a short shaft. I dont mind putting more money in it as long as I can trust it to crank and run when I need it. Thanks for any good advice...

Re: 1974 Johnson 6HP model 6R74C

Start with these and let us know what you find gl

http://forums.iboats.com/showthread.php?t=158071

http://forums.iboats.com/showthread.php?t=158086

Re: 1974 Johnson 6HP model 6R74C

Ok, Thanks for the advice... The second thread seems to be more appropriate for my motor since it dont have a battery. I did pull both plugs and both are firing real good. I did notice that the top one is fouled real bad.(a lot of gas oil mixture there). The bottom one looked normal. I guess my plans are to drain the lower unit, check out the old stuff and put in new stuff. Then either order a new fuel pump or kit and rebuild the carb. I guess I ought to pull the flywheel while I'm at it and change out the points and condenser??? I do have a compression tool and could check that too ... Or.... I might just take the lil feller to a reputable mechanic and let him do the carb, pump, points and what not. I do have plenty of tools but no experience with small outboards or large ones for that matter. I know it will take longer and more money at the shop but I would rather have it done right and by someone that knows what they are doing cause I would just be winging it... What's your expert professional opion???

Re: 1974 Johnson 6HP model 6R74C

They are fine running and dependable motors. Your plan sounds reasonable. It is not beyond the capabilities of someone with some mechanical abilities. You say you have plenty of tools. That is a good sign. At the other end of the spectrum, there are those who post here that should leave stuff alone. Of course, I am sort of biased, since I am a retired professional outboard mechanic.

Re: 1974 Johnson 6HP model 6R74C

well I really appreciate your comments, especially coming from a professional. Well I been messing with that Johnson off and on all day. I mounted it on my 14' and the two really look like buddies. I did remove both plugs and checked the compression and the results really impressed me. The top side was 85-86 lbs and the bottom was 84-85 lbs. What do you think??? Also I been reading a lot of stuff on here and it got me thinking. As I mentioned earlier, it runs about mid range better and it just dont seem to ever get reved up at full thottle. And there is a lot of gas/oil in the top cylinder and seems to be a lot in the water in the barrel. Sooooo... Does this baby have coils??? If so, Where are they located??. I know I need a manual and Im gonna get one. I am really beginning to feel challenged to do some of this work myself. I think I can do the water pump, fuel pump and maybe the carb. points and condenser, I might do that. If I can get the flywheel off. But before I tackle that or the carb I will get a manual... Well tommorow I will change the stuff in the lower unit out....Later

Re: 1974 Johnson 6HP model 6R74C

Gl, just take er one step at a time, there's always someone on here to give you a hand or a tip. When changing out the lower unit oil, make sure you replace the drain and vent plug gaskets, they're the number 1 spot for water intrusion into the lower unit. Check for a milky white or chocolaty appearance in the first little bit that comes out, the water will always sit at the bottom. ANd make sure you buy a quality bottom end fluid reccomended for your motor. Pump it in from the bottom until it comes out the top, replace the vent plug(top) then the bottom. If it is milky, you can put some kerosene or diesel fuel in, turn the prop by hand, let it sit a while, then drain and add the oil as usual to help clean it out.

Re: 1974 Johnson 6HP model 6R74C

Thanks for that bit of info... What would be a good gear oil for the unit?? I saw the Wal-Mart brand, was wondering about that and sythetic?? Or should I use somthing different? What do you think about the compression readings?? Where are those located? Do I use a sealer on those gaskits? Both sides? I would appreciate some info. Thanks... By the way, I'm not knew to the boating world, I still have a 1977 King Bee Bumblebee with a 1977 Evinrude 140 V4 I purchased in spring of 1980. I did have a new powerhead put on it a month after I purchased it. She's still as strong as a horse. Never a problem with her except cables every few years. Thanks.. Fishermanms.

Re: 1974 Johnson 6HP model 6R74C

for gear oil, I usually use name brand (shell) marine gear oil. Whatever you use it should be marine gear oil because they can emulsify a bit of water better than regular gear oil. You don't need sealant on the screw gaskets. By the way, when you change the impeller, that 6 hp has a little roll pin that goes cross ways across, near the top of the drive shaft. So once you get the gear linkage disconnected, you need to turn the drive shaft a bit (turn the prop with engine in gear and plugs out) until the little pin lines up with a slot (which you can't see)... then it will drop. Otherwise it will only come down about 3/8"

The coils etc are under the flywheel... you need a puller to get it off. Don't use a jaw puller, pull from the bolt holes in the flywheel. An automotive harmonic balancer puller works nicely (use quality bolts)... they're 1/4" 20 tpi. You might want to test the spark properly before you go that route.

It could easily have a carb that is varnished up inside if the carb wasn't drained before it sat for years...

If it were me, I'd check spark (probably pull flywheel anyway to see if coils were cracked, if so, replace), I'd do the gear oil thing, change the impeller and do a thorough carb disassembly & cleaning. If it has a cork float, I'd replace it with a modern type. Then I'd see where that leaves me. The stalling at low speed is typical of a dirty carb.

Re: 1974 Johnson 6HP model 6R74C

Thank you for all that good advice and information... I will need it. I built a stand today to mount the motor on out of 2X4's. I had to do that. I also have another question. This motor has an Evinrude whole mounting bracket including tiller thottle etc mounted to the Johnson. The man said he damaged the original with a bush hog some way or other. The whole thing works... BUT, you can move the motor up and down the different notches when you flip it on release but the whole motor wont swing free and staight out from the transom ...say when you get on the trolling motor or need to raise it up over a stump or something. There is a hand bracket that protrudes out in front of the controls that would keep it from doing that anyway. Is this the way this motor is suppose to be???

Re: 1974 Johnson 6HP model 6R74C

Hey fiserhman...

I'm doing the exact same thing here. Mine is a 6r73s that sat for a couple of years. Change the gear oil, got fresh gas, checked the plugs, and fired it up tonight. Same thing as yours. Runs then dies...and blowing alot of smoke too. I have a carb rebuild kit coming alot with points condender and impeller. Hopefully this weekend everything will be here. I'll take pics as I go through it. Between the two of us, perhaps we can get them running.

Re: 1974 Johnson 6HP model 6R74C

To see pics of it click on the attachments

Re: 1974 Johnson 6HP model 6R74C

Bill, Did you buy yours from that same fella I did???? Sounds like it. Actually I believe every word that man told me. If I sat here for two years and did nothing I would be in worst shape than my Johnson... Or should I say Johnson/Evinrude/... Well good luck on your's and I really think from all I have read here, we are on the right track... Keep me posted. You will finish your's first because I aint ordered nothing yet. Not sure what all I will order yet but most likely will do everything you do...

Re: 1974 Johnson 6HP model 6R74C

Looks very very familiar. I found mine at a yardsale with a boat. I have another thread going in restoration that has pics. The engine is real clean and I was told it only had about 30 hours on it.

Bill

Re: 1974 Johnson 6HP model 6R74C

Fishermanms, if it makes you feel any better, I just paid $615 plus shipping for a 1975 Johnson 6hp. With what you paid, you still can afford to put a little cash in yours.

Re: 1974 Johnson 6HP model 6R74C

Hi again,

I'm not sure, but I think your the transom bracket might be off an older motor (?). Does it have a model number plate on it? I think it's a bit different from how my '75 looks. The handle thing should pivot with the motor (the whole thing rotates at the pivot point). If you have it on "release", try tilting it by standing behind it, grabbing the leg and lifting it up. It may be quite stiff and you might not get enough leverage when it's on a stand to do it the normal way from the front. (or you'd tip the stand over) On these motors, the only thing keeping them up once they're tilted is the friction caused by tightening the pivot bolt. That means if they're gonna stay up once they're tilted, they need to be stiff to tilt... If it was used as a kicker beside a larger motor, it could be someone adjusted it to be very stiff (so it doesn't keep dropping down when it's not in use). Mine is quite stiff to tilt, but when its fastened to the boat works fine. Or could it be that the "release" isn't working right? but if you can adjust the trim pin, you must be able to tilt it a bit which makes me think it does release.

Good luck.

Re: 1974 Johnson 6HP model 6R74C

Okay, first of all you've got a Heinz-57 on your hands there. The transom bracket is Evinrude, the rest is a Johnson. So, I'd go by the model# off the welch plug rather than the transom bracket (welch plug is the quarter sized wafer on the powerhead) they might both be '74, they might not. A whole pile of years interchange there.

Secondly the run-stop-run is _probably_ a bad fuel pump. You can rebuild or replace. While you're at it, you should rebuild the carb. Might be good to do get running what you can, and figure out the fuel pump later. If you keep pumping the bulb will it stay running? It sounds like this motor sat awhile, could be all kinds of fuel delivery issues here.

Thirdly, 85 is low for compression. That said, one gauge's 85 is another gauge's 110. Do you have any way of calibrating that compression gauge to figure out what you have.

Four - no matter what #3 turns out to be you should do a decarb. You may very well have some stuck rings. Deep Creep (seafoam), PB blaster, Marvelous Mystery Oil, ATF & Diesel - choose your penetrating oil poison. Apply and soak your top end in the stuff over a few days and retest.

Five - on that vintage, pull the flywheel and inspect the coils. If they're cracked or othewise nasty looking replace. Re-gap and clean the points at any rate.

Re: 1974 Johnson 6HP model 6R74C

The short run and stop could be caused from the vent in your new fuel tank not being open also. You can test to see if it is the fuel pump by squeezing the primer while its running and see if it still dies. Good luck

Re: 1974 Johnson 6HP model 6R74C

Half of the the time, motors that have been stored for a while have the common problem of gel in the carburetor that is left when the gasoline evaporates. In the rush to start the motor, any of that junk that is left in fuel lines and fuel pumps gets sucked into the carburetors as well.

Re: 1974 Johnson 6HP model 6R74C

Fella's.... Ya'll know some stuff. I appreciate all of it. Backing up a bit there the Evinrude bracket does have a serial number on a plate. It's 5516-06615. I have looked at a 74 Johnson bracket and it looks the same as the Evinrude. But cannot see the deep down details. My tank is new, fittings new, hose etc all new and I do unscrew the air screw on the tank. Today at lunch I have squited a bunch of PB blaster in both cylinders while it was mounted on the stand. About 3-4 minutes later I noticed oil/pb dripping out of the exhaust and also barely leaking from a little screw right above the prop on the bottom of the foot. I took the motor off the stand and laid it down on its side with plug holes facing up and letting it soak. So i don't know but maybe there is some rings stuck??? Or wore out or both? Didn't know that around 85 lbs was low on the compression side or not... But they both were so close, (within a couple of lbs). I'm still debating on whether to do the easy stuff now but don't want to do all that and then end up needing a rebuild in the block. I guess I will wait untill I get some more opions here about the leaking and readings and will also take your advice and get another reading in a day or so. Where is the best place or some good places to shop for parts on line??? Thank yall so much. You all have been so much help.... Fishermanms.... The ms is for Mississippi...

Re: 1974 Johnson 6HP model 6R74C

I think your bracket is fine, but it's the same bracket for a whole slew of years. So, could easily be a '74 bracket and a '79 motor or some other combination. That may be an issue when ordering parts. You should look on the powerhead for the welch plug and read the model number there. That'll give you the right year when ordering parts.

Unless you set the pistons to TDC, you'll get any excess lube leaking out the exhaust ports - perfectly normal and okay. You may want to set one to TDC soak overnight, then do the other afterwards.

About the compression numbers, unless you've calibrated your gauge those numbers are meaningless. It's somewhere in the neighborhood of 85psi - could be +- 30psi (let's hope +) depending on the particular gauge. All you can really tell is relative pressure, they're close and that's good.

iboats is as good a place as any for online parts.