84 Johnson seahorse 70hp starting issues

[bp1313]

Hello everyone,

Help is appreciated

Here's the deal. I've got an 84 Johnson seahorse 70hp that has been in the garage (off the boat) since purchase. I took the motor off to rebuilt the boat and have since reattached it. The motor has run, turned over yesterday and today, but isn't turning over now.

symptoms...

the first time we hooked up the battery to start the motor I cranked really nicely. After 5-6 sec of cranking I let off the starter. Then I tried again... I heard a click (sounded electrical although who knows...) and no starter action. Battery is good. Have tested and tried multiple batteries (including a new one) so I'm confident in that. Cleaned all connections and tried again... turned over nice again!

5-6 seconds and then let off. Tried again... click and no starter action again. Any Ideas? Starter..solenoid?

Thanks for anything you've got. Let me know if you need me to run tests or provide more information for possible fix.

 

[Joe Reeves]

Re: 84 Johnson seahorse 70hp starting issues

Either you haven't cleaned all connections (and the components the cables connect to) properly. Did you clean the ground cable surfaces? OR.......

The starter armature commutator has a dead spot. To check this, simply turn the armature a 1/8 or 1/4 turn to have the brushes landing on another portion of the armature commutator.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

Thanks for the reply.

I've removed and cleaned all connections, wires, and what they connect to. I tried turning the armature... nothing yet. Any chance it could be the solenoid?

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

Hey Joe,

Turns out you were right on. I couldn't see it until it was dark, but there was a spark coming off the battery because the cables weren't tight enough. It's turning over like a champ now. Couldn't get it to fire up though.

I'm almost 100% positive I've got fuel, so I'm wondering about spark. I'm going to replace the spark plugs in the morning (because they're old and need to be replaced) and I'm going to get a tank of fresh gasoline as well.

Keep ya posted. Thank you.

 

[Joe Reeves]

Re: 84 Johnson seahorse 70hp starting issues

Don't guess at it!

Check the compression... what are the readings?

With the plugs still removed, check the spark which should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?

The gap is important... checking spark by using the s/plugs is a waste of time.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

compression was tested when I purchased the boat. 104 on all cylinders cold. With new plugs in she fired right up, but would stall out and die after about 5 seconds. After some tweaking and additional attempts... she's starting and running for up to a minute... but still stalls out and dies after that.

I'm weary of trying to run it in the driveway at all because it's not peeing. I'm going to try and drop it in the lake later and see if that changes. Is it true that it might not be abnormal for it not to have a stream coming out with muffs on?

So... I've got spark. It's looking more like a carb/fuel issue. What do you think?

To check the spark with the plugs out... how exactly? Sorry if that's a dumb question.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

Update....

I put the boat in at the local lake (with an electric motor to be safe ...) I put seafoam into the gas to try and make sure the carbs were clean as well.

I prime the bulb until it's tight and then start the motor. It fires right up each time. Then after about 10-15 seconds the rpms slow until she dies. I can start it back up...and after a couple seconds and then it dies. I reprime the bulb (because it's not tight anymore) and start it up again. It runs for the 10-15 seconds again and then slows and dies. Any suggestions on what to look for?

I figure i'll need to make sure the fuel pump is working (but if the bulb isn't tight anymore...wouldn't that suggest it is?) and the lines are clear.

The other issues is that it never showed water out of the peehole. I don't know when the last time the impeller was changed...so that's going to get done either way. It could be blockage... but the tabs on the boat were 2007... so I'm guessing it's been awhile.

Thanks for any help and advice. It's much appreciated.

 

[Joe Reeves]

Re: 84 Johnson seahorse 70hp starting issues

The fuel primer bulb is only tight (hard) when you prime it. It does not stay hard when the engine is running. It is normally laying in a horizontal position and it is normal for the fuel level to drop down to the halfway point inside the bulb.

If you constantly pump the fuel primer bulb (acting as a manual fuel pump) does the engine continue to run? If it does, that indicates that either the fuel pump is faulty, the hose leading from the pump to the crankcase (pressure hose) is leaking, a fuel/air leak exists somewhere between the pump and the fuel supply, or the engine has a problem with its crankcase pressure.

Let us know what you find.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

Thanks Joe!

What I found out so far...

The impeller is pumping water nicely. The hose coming out of the block had an obstruction and has since been cleared. Nice stream now. The pump is working up to the fuel filter at least. The engine stalls out because it's starving for gas. I'm tracing the gas from the tank to make sure everything up the line works. I'll keep you posted.

And again... many thanks for your advice.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

sorry...forgot to answer. No...when I continue to prime the bulb it didn't help.

pulled the fuel filter, the lines to the carbs, and pulled the drain bolts on the carb bowls. One them had a few particles in it..but mostly clean. Kept running it and now it'll idle nicely. I can throttle up to about half and then it bogs down and starts to die. If I pull the throttle back all the way it'll pick up again and idle without dying. 50% or more throttle and it cuts out.

thoughts?

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

another symptom for the experts. While it's idling with the cover off I put my hand over the air intake for the carbs one at a time. Putting my hand over the top two doesn't have a huge effect and if I hold it there it takes5-10 secs for it to slow the motor almost to stall. When I do the same to the bottom carb the motor dies almost instantly. Good suction from the upper two not as good on the bottom.

I don't even know what that means and I'll try to do research. anything?

 

[fishman204]

Re: 84 Johnson seahorse 70hp starting issues

you still have dirt in the upper carb not running rite on those cyls the spark plug color should be different from upper to lower cyls when all 4 are firing correctly plug color should be similar also mite be fuel line

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

pulled the carbs off and will be cleaning them and installing the new gaskets and parts from kits. Any tips/tricks for doing it?

My plan was to soak them, blow them out with compressed air, soak again, and blow them out again while looking for any visible gunk. Then replace all the new parts and put them back on.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

alrighty...

Carbs are clean and I'm having soo the same issue. I replaced the fuel lines in the motor and it's alerted me of a problem. No gas is getting to the top two carbs. The engine will stay running if I activate the choke...but will die If I don't. I pulled the fuel pump apart to check the internals and it looks ok. I pulled the fuel line off and turned it over and fuel spits out of the fuel pump. I can't imagine it's a stuck needle valve (x2) because I just cleaned and replaced them. Thoughts?

Not enough pressure from the pump? (or worse??)

 

[fishman204]

Re: 84 Johnson seahorse 70hp starting issues

The primer ball should be able to push fuel into the carb bowls.Are your floats adjusted rite I think on those carbs you can hold thould e carb upside down and level then the float should be level aswell I THINK someone else may know better Is th fuel line soft going to the bad cyls might be collapsing

 

[Joe Reeves]

Re: 84 Johnson seahorse 70hp starting issues

Easy to check if fuel is entering the carburetors.... After pumping the fuel primer bulb up hard, loosen or remove the drain screw from the bottom front portion of the float chambers.

Set the floats as follows:

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

Thanks guys. I'll try giving the floats an adjustment tomorrow. I'll let you know what happens.

We took it out today after messing with it. she'll get up to about 1/3 power and that's it. I'm hoping that it's an issue with the needle valves and float setting as indicated. we'll see.

Thank you.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

The problem that was causing no fuel to get to the carbs was the needle valve seat. Backing them off almost a full turn allowed fuel to enter and fill the bowls. I don't have a service manual...so at this point I'd just be guessing where they're supposed to sit at to run properly.

I'll adjust the floats today to match the instruction above and see what happens.

Anyone have experience with a link-n-sync on this motor? Are there any other adjustments that I might need to know about on the carbs? They seem really straightforward and lack many moving parts (that would indicate the ability to adjust.)

Thanks guys.

 

[Joe Reeves]

Re: 84 Johnson seahorse 70hp starting issues

The problem that was causing no fuel to get to the carbs was the needle valve seat. Backing them off almost a full turn allowed fuel to enter and fill the bowls.

I'm trying to figure out what you're speaking of. There is no adjustment pertaining to the float needle valve seat which is what would allow or shut off any fuel entry to the carburetor float chambers.

If you're speaking of the slow speed adjustable needle valves... they allow the fuel that is within the carburetor flow to the designated cylinders. Note that in 1984, various 70hp models had the adjustable slow speed needle valves while other models incorporated the fixed slow speed jets.

For the adjustable slow speed needle valve models, adjust as follows.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[bp1313]

Re: 84 Johnson seahorse 70hp starting issues

Hey Joe,

I really appreciate the help. I'm going to have to take some pics so that I can be sure we're on the same page as to what to adjust. I think (and no I'm' not positive) that I have the fixed jets. The only thing that makes me say that is I'm struggling to find something to adjust. When the carbs are all together and attached to the engine... there's really only 1 screw that can be turned. I believe it's just a cap as well. I'll get some pics together and get back to ya.

Thanks a bunch.