Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor dies.

[MAW31]

This is the second time we've had to paddle back to the dock.

info: 1989 Johnson 115 V4.

knowns: new plugs, tested sparks with timing light. checked timing. removed carbs and checked all jets and orifices.

symptoms: we idled for almost 20 minutes at the dock (in water) after testing all the specs above and everything looked and sounded good. so we headed out for a full throttle run but we never got out of the canal.

The motor just puttered out...like fuel just...stopped... and was... hell to start.

The ONLY thing that would get the motor going was a half throttle start to scream, then pump the choke like hell while we got motor down to prop engaging rpms and while I held the choke in we limped the boat back to the dock.

However, at some point, it would seem like I didn't need the choke anymore. Like the problem was intermittent.

Observations: fuel pump bulb was nice n full and not deflated. We could crank the motor over like crazy but unless we went to half throttle, we got nothing, and I mean nothing. no sputter, no coughing, nada.

possibilities? probabilities?

a. fuel pump? (intermittent?)
b. power pack? (but timing light picked up triggering)
c. could a single bad coil once warmed up create this scenario? (we think not and also tested right then when it happened again)

we are befuddled and ask your help.

Ideas as to what could be causing this behavior? (As always, thank you all)

 

[Daviet]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

a. You can override the fuel pump by constantly pumping the primer bulb.
b. I would think that if the timing light showed spark the pack would be ok.
c. I wouldn't think a coil would not cause the problem you describe.
Have you checked the timer base to make sure it is moving freely and not sticking at times?
Did you do a lynk/synk after you overhauled the carbs?

 

[MAW31]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

Thanks for your input.

Yep, we did check the timer base for full throttle movement, and checked the timing advancing from idle through mid throttle.

Is it possible that the pump is working, but poorly and not getting enough fuel pressure?

Its just that it seems to run just fine and then acts fuel starved. only thing that keeps it running is choking it.

 

[Daviet]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

If you constantly pump the primer bulb you will over ride the pump, if helps, time to rebuild/replace the pump.
In my experience, if you can keep an engine running by using the choke, you have a carb problem.
I didn't sse a 115 in 1989, might have missed it, could you post a model number?

 

[the machinist]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

Could it be something inside your fuel tank that is getting sucked over the pickup when you open the throttle?

 

[MAW31]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

If you constantly pump the primer bulb you will over ride the pump, if helps, time to rebuild/replace the pump.
In my experience, if you can keep an engine running by using the choke, you have a carb problem.
I didn't sse a 115 in 1989, might have missed it, could you post a model number?

Daviet:

Ok. Lets roll with a possible carb issue.

If i'm thinking it could be a carb issue, then i'm having a hard time explaining the behavior.

Idles fine for 20 min and leaves dock with nice idle characteristics, runs for 5 min at no wake speeds, and then without throttle change...Phtooey. Motor stalls. quick check of primer bulb and its full.

The killer here is how difficult it is to start; and when it does, we're at half throttle. It screams, sputters and dies (unless i'm on the choke) or keep throttle up. prob there is, we cant get into gear at those revs.

We know I had days ago done a carb clean on both carbs, taking them off the motor and over to the bench checking idle and main jets and the vacuum orifices, checked float operations and settings. The carbs were clean. I found no smoking gun there.

And so i'm having great difficulty matching the experience to a probable cause.

I hope your with me on this as I've been really methodically trying to study the witnessed behavior to a scenario that could explain it.

I will however, pull the carbs and check 'em.

thanks again.

 

[Willyclay]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

The killer here is how difficult it is to start; and when it does, we're at half throttle. It screams, sputters and dies (unless i'm on the choke) or keep throttle up. prob there is, we cant get into gear at those revs.

Sounds just like my bud's 1991 Evinrude 60HP that I helped him with last year. First problem was bad gas. Once we had good gas, we did a link&sync and it started and ran perfectly. May not have anything to do with your situation but wanted to share my experience. It's usually the simple stuff. Good luck!

 

[MAW31]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

Update.

Took carbs off this morning. One of the screws on the carburetor lever pin that holds the two butterfly valves on is missing its head. The shaft of the screw is in the lever still.

I'm thinking this could be a huge contributing factor even if the butterfly seems to be solidly holding on.

Also noted the backside of the butterfly valve appears to be losing its galvanized coating and so went to see if the butterfly valves can be purchased as a part but did not see a schematic breakout for the valves.

Is it that the carburetor body is sold with the lever and butterfly as a unit??? Might there be another source?

thanks all.

Or more directly is there no way to replace the butterfly valve and lever?

 

[Daviet]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

Here is a breakdown of a 1987 115hp, couldn't find one in 1989. It does not show the throttle plates as being available as a seperate part.
I don't think I have ever tried removing the throttle plates, maybe a salvage yard might be able to help you out with a complete carb or a carb body.
:: iShopMarine.com ::

 

[MAW31]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

Thank you kindly.

 

[Daviet]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

I wonder if the screw head is bouncing around in the reed valves and holding one of them open at times, might not hurt to check.

 

[iwombat]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

Sounds to me like gummed up idle jets. Might be starting on one carb only, then once you get under load it's just too starved to keep going.

 

[likitvi]

Re: Paddled back for 2nd time. Not getting 300 yards at no wake speeds, then motor di

To me this sounds exactly like water in fuel. I had exactly similar behaviour caused by that.

Check what your primer is feeding to the fuel pump, and if it looks bad pump the stuff out until it looks good. If you have a water separator in fuel system check it also. I pumped some 3 litres of fuel with water out from the 24l portable tanks and it had about 1l of water in it. After that those problems were instantly gone.