CROSSFLOW PERFORMANCE ?'s

[phx5kegsman]

Hello, I have a 1978 Johnson 115hp V4 on my '82 Ranger bass boat. This morning after fishing I decided to fool around a bit. I've spent the last two years restoring this boat & motor and I wanted to see how it handled, top speed, etc. I always run it WOT from one fishing spot to the next, but never for too long and always a straight shot. To the point, I was running it around the lake at WOT (about 5300 rpm) and did some sharp turns and experimented with trim. Ran it hard for maybe 15 minutes and then, coming out of a turn and (still up on plane) back to WOT. The motor lost power and seemed to stall. I have I have an auto/off/manual bildge pump switch on the inst. panel that has a green light for auto and red for manual ( I run it on auto with the green lit up). When the motor stalled the red light on the manual side of the switch lit up and flickered bright then faded. When I pulled the throttle back to neutral the rpm's returned to normal, red light went off, and seemed to go back to normal. I stayed in the lake for about another hour with no problems, although I stopped the "hot rodding", lol. Any thoughts on what happened?
Note: My cranking battery is brand new and my voltmeter showed motor was charging it. Actually, at one point the voltmeter showed it was putting out 17 Volts (is that normal??).
Any help will be greatly appreciated. Thanks!

 

[saltchuckmatt]

Hello, I have a 1978 Johnson 115hp V4 on my '82 Ranger bass boat. This morning after fishing I decided to fool around a bit. I've spent the last two years restoring this boat & motor and I wanted to see how it handled, top speed, etc. I always run it WOT from one fishing spot to the next, but never for too long and always a straight shot. To the point, I was running it around the lake at WOT (about 5300 rpm) and did some sharp turns and experimented with trim. Ran it hard for maybe 15 minutes and then, coming out of a turn and (still up on plane) back to WOT. The motor lost power and seemed to stall. I have I have an auto/off/manual bildge pump switch on the inst. panel that has a green light for auto and red for manual ( I run it on auto with the green lit up). When the motor stalled the red light on the manual side of the switch lit up and flickered bright then faded. When I pulled the throttle back to neutral the rpm's returned to normal, red light went off, and seemed to go back to normal. I stayed in the lake for about another hour with no problems, although I stopped the "hot rodding", lol. Any thoughts on what happened?
Note: My cranking battery is brand new and my voltmeter showed motor was charging it. Actually, at one point the voltmeter showed it was putting out 17 Volts (is that normal??).
Any help will be greatly appreciated. Thanks!

I say no but will let others pipe in. Blown rectifier I'm assuming.

 

[Chris1956]

Sounds like some kind of loose electrical wire. I am not familiar with your motor's ign system, so I cannot provide any specifics. Most ign systems ground to kill spark. Maybe a loose wire grounded your ign?

 

[phx5kegsman]

Does anyone know what the maximum output from the rectifier is? Mine showed 16.9V . That seems high to me

 

[saltchuckmatt]

Does anyone know what the maximum output from the rectifier is? Mine showed 16.9V . That seems high to me

Read some info that you might be using the wrong battery.

Are you running a marine deep cycle battery?

 

[phx5kegsman]

Oreiley's Super Start Marine group 27

 

[saltchuckmatt]

Oreiley's Super Start Marine group 27

The 17 volt thing seems to have many opinions online.

Certainly doesn't explain why your motor went down.

2 strokes love WOT......

 

[tphoyt]

I’m going out on a limb here and wondering if you had a couple things happen at the same time. Just a thought but maybe while doing the abnormal maneuvers you upset some trash in the fuel tank and possibly picked up a bit of water for a moment causing the loss of power but only enough to cause it to stumble for a moment. Do you have a fuel water separator by chance? Do you have an built in or portable tank?
Any chance you have some lose wires from the battery change? Is the battery strapped down so it won’t move around during sharp turns and maneuvers causing problems?
Just some thoughts.
Best

 

[flyingscott]

Pretty sure that motor uses a rectifier only. So higher voltages are normal make sure you are using a good non sealed standard battery. That style rectifier uses the battery as the regulator so you need to be able to refill it.

 

[phx5kegsman]

Today I did all of charging system resistance tests of the stator and rectifier as directed in the factory service manual. All passed! Tested the battery and it is in an overcharged condition(13.4V). It did pass load test.

To answer questions: Built in tank w/ water separator(newer filter).Recently had tank out and flushed it out the best that I could. Battery is strapped down and is non-sealed lead acid type.

That's the first I've heard about the battery acting as regulator. Would this account for the overcharged state of battery?
Also, I run two sonar fish finders off the cranking battery. Looking back I remember getting a "low battery" warning on one of them very early in the day. I turned them off and started the motor and ran for a bit and then went back to fishing, alternating sonar units (one on trolling motor and one stern), with no more "low battery" warnings.

 

[jimmbo]

Totally unregulated Charging System, Voltage will climb as the Rpms increase. Only use Wet Cell Batteries that have the provision to check the Electrolyte Level and add Water as needed. Sealed Batteries, and AGM(like Optima) are NOT to be used.

 

[phx5kegsman]

So, I'm wondering if I should have yet another battery for my fish finders. If I were to do that, is there any way to have that battery charged by the motor, as well as the cranking battery? Or will a freshly charged batter, used only for my fish finders, last all day on one charge?

 

[saltchuckmatt]

So, I'm wondering if I should have yet another battery for my fish finders. If I were to do that, is there any way to have that battery charged by the motor, as well as the cranking battery? Or will a freshly charged batter, used only for my fish finders, last all day on one charge?

A two battery system is always better and I wouldn't be caught without them. With a two battery selection switch whatever battery needs charging you just switch too.

Still doesn't explain why your motor bogged down.

 

[phx5kegsman]

No it does not. Just grasping at straws here... Could making sharp turns (tbh, I did a couple of rather tight "figure 8's) cause the fuel pump to suck air or perhaps do something to the float(s) in carb(s). Again, just guessing.Most bass boats have fuel tanks under the seats ,but mine is an older Ranger Boat (1982) and The fuel tank is located at the stern of the boat in the battery compartment. Its a large aluminum tank (15+ gal). The fill tube is on the portside top of tank and the outlet tube is on starboard top of tank. From there fuel goes through filter/separator then to motor.

 

[saltchuckmatt]

No it does not. Just grasping at straws here... Could making sharp turns (tbh, I did a couple of rather tight "figure 8's) cause the fuel pump to suck air or perhaps do something to the float(s) in carb(s). Again, just guessing.Most bass boats have fuel tanks under the seats ,but mine is an older Ranger Boat (1982) and The fuel tank is located at the stern of the boat in the battery compartment. Its a large aluminum tank (15+ gal). The fill tube is on the portside top of tank and the outlet tube is on starboard top of tank. From there fuel goes through filter/separator then to motor.

Well 15 gallons on an older carberated 115 doesn't last long. (In comparison I have 37 gallons on a Etec 115)

There used to be a formula for gallons per hour on two strokes based on cylinders and throttle.

Anyhow, maybe you were low on fuel and just sucked up some air loosing power and then it recovered when you slowed down.

I would buy another 6 gallon can if you plan to be out long.

 

[RBoyd1971]

I had the exact same thing happen a couple of times recently with my 1982 90hp. I would be running wide open about 40mph then it would stall out. Eventually my power pack in the starboard side died. I found a couple of things that could have caused the stall though. While the cowling was off, I noticed when I squeezed the primer bulb hard gas was shooting out around the cover on the fuel pump the hose hooks to. When I got to looking at it good, I noticed the barb was lined up with one of the screws and wasn't letting it seat on the gasket good. I turned it so it was between screws and tightened it good and no more leaks. It may have been sucking air at WOT. As far as the power pack, it was dated to 2009. As a precaution I went ahead and checked for voltage on the kill switch wire and it was around 0.2 volts which is within spec. I put a new CDI Power pack on it and it's running great again. Just saying all this for some ideas of things to check out. The power pack quit in a weird way. It stalled twice on this outing. After the first time, the engine started a quick miss slow speed and then lost power when I went to WOT again. Checked fire on all cylinders and noticed no fire in either of the starboard cylinders. It had stalled twice on another outing in the same way, just recovered then when it did.

 

[phx5kegsman]

Thanks!I will check the power packs, provided there's a procedure in the manual.

 

[ct1762@gmail.com]

Thanks!I will check the power packs, provided there's a procedure in the manual.

FYI resistance tests rarely show up out of spec on the stators charge and sensor coils. its the cranking voltage with a DVA that is truly useful.

 

[flyingscott]

FYI resistance tests rarely show up out of spec on the stators charge and sensor coils. its the cranking voltage with a DVA that is truly useful.

When did that start? I have found plenty of bad stators by being out of spec.

 

[phx5kegsman]

Bought a rectifier ( Sierra 18-5708) off Amazon), installed it, and took the boat out last Friday. Started up ok, ran good, but then I noticed my tach was out and voltmeter gauge was reading 12.9 (battery voltage) and dropping because of accessory load. Bad Rectifier out of the box?? As for power packs. I don't have any of the test equipment noted in the manual. Is there any other ways to test them, other than replacement?

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