I think I messed up my motor

About a week ago I got my first boat. It is a 14' Crestliner that came with a 6 hp Johnson outboard. Well, I think I might have tore up the motor all ready.

When I went to buy the boat, the guy started the motor in a trash can of water and it sounded like it was running pretty well. A couple days later my son and I took it out for the first time. I didn't know there was a difference between weedeater gas and outboard gas so I filled it up with gas and the same oil I used for my weedeater at a 50:1. Apparently the motor didn't like it because it ran like crap. It would start easily and as long as it was revved up a little it wouldn't die. It would run great in neutral, but as soon as I would put it in gear it would immediately bog way down. I figured it was just where It had been sitting and needed to be run for a while to clean everything out. Every once in a while it would take off like it should but then bog right back down. After about an hour we called it quits and decided to go back home. When we got to the dock another boater was there and advised me to use Seafoam on the motor. I put some Seafoam in the fuel tank, ran it for a little while in a trash can of water and all seamed well. My daughter and I took it out this time and we got about a half mile from the dock and the motor died. it would restart but then just die again so I paddled us back to the dock. I found out about marine 2 cycle oil when I got home. I put fresh gas and marine 2 cycle oil in it but I'm getting the same thing still, hard start then it will run for a few seconds then day. It makes no difference weather I pump the primer bulb or not.

Any Ideas on how bad I messed it up running the wrong oil or other things I should check before I tear into it and attempt a complete rebuild?

BTW it is a 69 Johnson 6hp model number 6R69M.

You could run that motor using 30wt motor oil for your mix and not hurt it.

Sounds like you need to pull your carb and clean it.

Yeah you did NOT ruin your motor although I do recommend using the proper oil from now on.

Ok now let me let you in on a little secret, just because a motor runs good in a barrel does not mean the motor runs good or at all when under a load on a boat. And I suspect the man that sold you this knew this

Next, have you done a compression check? Carb may just need a cleaning? Also do you know that your motor does not have a kill switch, by turning the tiller handle all the way to the right it kills the motor. Make sure you are not doing this and thinking the motor is stalling on its own (seen this before in another thread). Your motor could also need new points, condenser, coils and plugs? Have you adjusted your slow speed idle screw properly? Turn it all the way in to the right gently seating it and back it out 1.5 turns to start with. Then adjust in 1/8 increments until you get the motor at highest idle, then back it off about a 1/4 turn. Fine tune the idle in the water on the boat and in gear at slow idle.

There are several problems that this could be but we got to start somewhere. I would compression test asap to see if the motor is merely an anchor. If you got good compression then we move forward from there

I'm glad to hear I didn't ruin it by running the wrong oil in it. I'm off work today so I will get a compression gauge and check that today. As for the slow idle, I looked at a diagram of the carb and apparently there is supposed to be some type of packing around the needle and mine is missing. The needle just spins freely. I'm going to look for a place around me that sells carb rebuild kits but I will most likely have to order one off the internet. Any suggestions on how to get the flywheel off to check the points and other things under there? Thanks for the advise.

Well, I believe my motor is shot. I went to Autozone and got a compression tester this morning and checked the compression and it wasn't good. About 40 psi per cylinder. I just don't get why it had moments where it seemed to run great then bog back down when I had it out on the water?

Pull your cylinder head. Some of the old 6hp engines and almost all of the old 5 1/2hp engines had a head gasket that had no fire ring on them. Those old gaskets were prone to burning through. Hopefully yours is one of them. If so that will account for your compression numbers.

Clean the Carb. Sounds like mine when the float was sticking. Mine did the same thing last weekend. I tapped on the bowl with a screw driver handle and it was normal again.

I wouldn't think that motor would start very easy or at all with only 40 psi compression. Did you have the throttle wide open when you were checking the compression? It it's having intermittent spurts of running good vs bad as you describe, I would suspect it to be a fuel related issue rather than a compression problem.

Check the simple things first. Did you have the vent open on the tank?

Additionally, If you just got a motor with unknown history from someone, I suggest replacing the water pump/impeller as soon as you are able. That'll save you some potential hassle in the future.

Good luck with it.

kofkorn said:

Check the simple things first. Did you have the vent open on the tank?

Additionally, If you just got a motor with unknown history from someone, I suggest replacing the water pump/impeller as soon as you are able. That'll save you some potential hassle in the future.

Good luck with it.

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+1 on the vent.

Actually the first 2 times I ran it, I didn't open the vent. Didn't even know there was one. The last few times I ran it , I had it open but it didn't make any difference. I also tried to pump the primer bulb while the motor was running but it didn't help either.

I took the carb off and cleaned it today with no improvement. I have to order a rebuild kit because there is no place local that sells them.

I plan on pulling the head tomorrow to see what's going on in there. I did look inside the spark plug holes as best as I could and they look pretty good. There is some carbon build up on the top of the piston but cylinder walls look good. I know it's just a youtube video, but I seen a guy testing the compression on a motor that had rusted cylinder walls and heads that still made over 60 psi of compression. Mine looks a lot better and only makes 40? Is it possible that something could be restricting the air going into the cylinder?

Pull the flywheel and check/replace the points and condenser. Check the coils for cracks. Replace if it is.

Other causes for low compression:

1, Stuck and/or broken rings
2, Bad compression gauge or gauge not sealing in spark plug hole
3, Head gasket leaking
4, Warped head
5, Cracked block or head
6, Operator error - not preforming the test right.

first thing, when you did the compression test, how many pulls did you do? i will do at least 3-4 pulls. you can also put a socket adapter on a cordless drill and pump the motor a bit using the nut on the flywheel. did you pull both plugs, put motor in gear, open throttle full, then perform the pull test.

compression should be in 5% at least in the 80 lb range. what year is the motor? sounds like a fuel issue. clean the carb and replace ir rebuild the fuel pump and change all the hoses. i think the hose is 5/16 and 3/16 from the fp to the carb. carb kits are cheap. take it all apart, soak it in pinesol and blow all the passages clear, make sure you get the little pot metal cover off and replace the shot inside. fuel pump is easy to rebuild, you just need patience.

+1 on the impeller change. period no ifs and or buts. change the impeller at least. if the housing is scored, warped or damaged replace the whole pump. around 50 or so.

it all lies on the compression. if its 60 pounds, or less then i would not spend any time or money on it. unless you want to rebuild the motor?

jmho

dino

Do all of the above and get a new spark plug properly gapped