30 hp johnson propjet troubles

[Ken Basaraba]

Have been reading these forums quite a bit. I am new to outboards and 2 strokes. I have been boating all of my life , my parents have pictures of my drinking my babybottle in an old searay. I have sold my last cabin cruiser and just want to bass fish for the next couple of years and explore Georgia lakes, while i save for a new cuddy cabin or open bow.<br /> So.., on to what i need help with. I have a 1994 military surplus 30 hp 2 stroke johnson. Very happy with the power of it. Had it for about 3 weeks. Bought used from www.smalloutboards.com , and they still have pics posted. It is propjet driven. It starts on the first pull every first start of the day. But after i have been running it for 15 min or so, allow it to cool while i fish a spot, then try to start it , it takes 6-7 pulls. They day i recieved it i replaced the water pump (for good measure) and plugs, and lower unit gear oil. New gas tank, fuel filter , bulb and line. Getting spark, but plugs are a little wet with oil when i pull them. Using standard o/b oil 2.5 oz per gallon. Runs very smooth at idle and wide open. No sputtering or jumping. Awesome motor, my 16 ft 74' polarkraft jon flies with it. Planes instantly and am at top speed in 10 - 15 seconds. But this one little nagging problem......<br /><br />p.s. it has a de-watering valve and am not sure what thats for.<br /><br />Thanks in advance for any good soul willing to help. God bless you

 

[Harker]

Re: 30 hp johnson propjet troubles

I bought one of them last year and have the same experience as you. It runs great and has tons of power but runs rich as hell. I think it is tuned that way because they were meant to be launched from submarines while submerged(hence the de-watering valve) I am going to replace the thermostat and rebuild and readjust the carbs and see if I can plug the dewatering valve holes because mine runs cold..hopefully the new thermostat and carb rebuild will make it smoke a lot less. The numbers on it show it to be a 35hp (aml35d on mine) I have mine on my Monark 1750MV alum jonboat and get about 22mph on my gps.

 

[phatmanmike]

Re: 30 hp johnson propjet troubles

i have an 88 evinrude 14hp , yes , 14hp, that does thee same thing, it turns out that the fuel is being "boiled" away after i turn it off, out of the bowl. it starts and runs great, but after sitting for a few mins, it takes like 5 or 6 pulls, but i dont mind, it runs like a bear!!!

 

[Ken Basaraba]

Re: 30 hp johnson propjet troubles

Thanks for the help, really appreaciate it, gonna look that direction.

 

[Ken Basaraba]

Re: 30 hp johnson propjet troubles

By the way where were those numbers on the motor?

 

[Harker]

Re: 30 hp johnson propjet troubles

The numbers on mine are on the motor mount..most of them mean nothing to laymen like us since they are military inventory numbers. My kill switch didn't work, does yours? I may get it on the water this weekend and run omc decarb stuff through it to get ready for tearing into the carb and thermostat.

 

[Ken Basaraba]

Re: 30 hp johnson propjet troubles

Hey my kill switch does work, but at times i have wondered if it was the source of my starting troubles. Imagine me laughing at myself when i first got it , and tried pulling it untill i broke the cord, then realized (being my 1st outboard) what that funny little red button was for ;-]. There is a sticker on my motor mount , but its totally painted over. Also i tried starting fluid and it didnt help. Still took 6 pulls. I wonder if oil mix should be cut a little.<br />Plugs have oil on them at that point.

 

[Harker]

Re: 30 hp johnson propjet troubles

Starting fluid is a big no no for 2 stroke engines...the plugs should have a little oil&gas on them but it sounds like a flooding problem. Your "dewatering" valve is pushed IN isn't it? I can't think of any reason to have it OUT unless the motor gets submerged. You may have a weak spark but it is more than likely the carb is just set up rich.

 

[Ken Basaraba]

Re: 30 hp johnson propjet troubles

had it out today. Leaned it 1/4 turn and is started no problem as long as i gave it no fuel. weird, if it was a car carb id say it needed a needle and seat. Do these kind of carbs have one? Never taken one apart. By the way someone stole one of my tail lights off my trailer. We came in late and one light was gone with wires cut.Snake creek ramp off of west point lake. Lame :[

 

[Harker]

Re: 30 hp johnson propjet troubles

Amazing the things a-holes will steal...Get a factory manual for Johnson 25-35hp 2 cylinder motors and it will be the best thing you can do for the motor...Can't remember the name of the guy I got mine from but it was here off i-boats..the manual guy .com or something like that he was very helpful on the phone.

 

[Ken Basaraba]

Re: 30 hp johnson propjet troubles

More on the motor saga, spent 4 days at carters lake in georgia fishing. AT the end when i came back in i was starting to lose power. So i rebuilt carb, and replaced the aging wires. Boom started right up and boy did it sound good. Ran for 10 min and then wouldnt start. Took it to big Earn the boat man. Hes been speeding up and tricking out boat motors for 35 years. Turns out i fried a ring on the top piston. He said thats probably the escess smoke reason. Also said that the navy probably put them up for surplus because they had reached near the end of a predetermined life cycle, and it was probably going when i got it.So, the good news, he says all the electronics are missing as woulb be in a normal motor. And when hes done replacing pistons, rings, and and punching it .030 over and using high performance parts i should get 5 more hp or better. He says its a superior motor and makes sence to rebuild it. He even offered me a rebuilt 25 hp for it. I said no, ill keep it and for a total investment of 2k all have a reliable 40 hp. New 25 hp tillers are 3k , so maybe you should check your compression .

 

[Harker]

Re: 30 hp johnson propjet troubles

Ken, what did he mean all the electronis as in a normal motor are missing? This engine has been fun trying to find all the nuances that differ it from standard motors..wish the Navy included a manual with them that told the story.

 

[Ken Basaraba]

Re: 30 hp johnson propjet troubles

Big Earn didnt get real specific other than to say that the tiller handle side of the motor has a mess of electrical missing. I mean to look at a new johnson when im at the marina next. He did say that the electrical for the choke and the choke itself are missing. He said very little left to go wrong. And the gear shifter is in the water pickup screen.