1996 SL700 Hot Start Issue

[K447]

 why having the trim motor connected makes the ski run better.

I found nothing that indicated why the engine stumbles when the white/green and white/blue wire is disconnected.

I did confirm that on the board I have +12v and -12v when pressing the trim switch. 

With the trim motor disconnected from the terminal board;

With one meter probe on battery negative, confirm there is no voltage on either of the Green/White or Blue/White wires from the handlebar switch (with switch not pressed).
One meter probe on battery positive, also no voltage measured on either of those switch wires, correct?

Measure with engine not running and again with engine running.
Should be the same ÔÇÿno voltageÔÇÖ results.

[MA-Chris]

On the positive note I got a new fuel sender float and now my gas gauge works properly.

I did the tests above and I did not observe more than 1v when the trim switch was in the off position.

I am going to wait until I get a working trim motor to troubleshoot further.

I did reseat all the grounds.

Chris

[K447]

 did not observe more than 1v when the trim switch was in the off position.


It might be worthwhile to ohm test the trim switch. Sometimes the switch internally corrodes or becomes damaged.

Disconnect both trim motor wires and the orange feed wires that go to the switch.
Each motor wire (Blue/White and Green/White) should show no connection at all (infinite ohms, no continuity) to both the orange switch wire and the black wire (with the switch not pressed).

Pressing the switch should cause direct connection (zero ohms) from Green/White to either Black or Orange switch wires. Press switch the other way should connect to the other wire color.
Same test with the Blue/White motor wire should have same results.

[MA-Chris]

Thanks, the new trim motor shows up tomorrow so I will start troubleshooting with that installed.

Looking at the schematic above, I have no idea why the trim motor being connected should have an impact on the ignition/coil and how the engine runs even if the trim motor is shorted out. Is it causing interference? So strange.

[K447]



Looking at the schematic above, I have no idea why the trim motor being connected should have an impact on the ignition/coil and how the engine runs even if the trim motor is shorted out.

Is it causing interference? So strange.

This is why I am suspecting a wiring problem/error and/or a trim switch problem.

[MA-Chris]

I received my new trim motor today, the seller failed to mention that the indicator cable was corroded shut. No problem, I just swapped the motor and gearbox into my jetski. I hooked a battery up to the ground and the orange terminal and the bilge pump came on and the trim motor operated flawlessly.

I also used a multimeter to check continuity of the trim switch and it seems to be working as expected.

It is supposed to be warm thursday or friday and I will get it on the lake again.

I have no idea what to expect if the problem resolved itself...

[MA-Chris]

So we had much success last night. What did I do?
1. drained and refilled the gas tank with fresh gas.
2. drained and refilled the oil tank
3. changed the fuel filters
4. replaced the trim motor
5. replaced the fuel float
6. washed the air filter
7. plugged and unplugged most circuits on the circuit board to check for good continuity.

Now:
The fuel gauge works
The trim motor works
I have also noticed that now since the jet is not pointed to the seabed, the steering is a little off. I can adjust that at the rear of the craft it seems.
We ran for around 1.5 hours and burned through 4 gallons of gas, does that seem right?
I would estimate the ski is running in the high 40s trimmed out, but I did not verify since I already lost one phone in the lake.
It accelerates so "hard" you really have to hang on.
Really pleased with its operation.

The intermittent hot start issue is back. Now in the ski's defense I was running with a pretty empty tank since we are at the end of the season.
For a cold start, with my left hand I hold the choke open and press start while feathering the throttle with my right hand.
Sometimes, with a hot start, the ski starts right up with a little throttle.
1/3rd of the time it is a few minutes of cranking before it catches.
At first I thought it was flooded, but that always does not seem the case.
Sometimes with 20 seconds of cranking it will smell like fuel, but every time it finally starts there are never big belching clouds of smoke that would indicate flooding to me.
This makes me feel it is a fuel delivery issue, not an ignition issue.
Thoughts?
My next steps:
1. Fill the fuel tank.
2. Replace all the fuel lines
3. rebuild the carbs
4. new ignition? I will not spend $700 on parts for this ski, so that is off the table.

How do I troubleshoot this further before I just start replacing stuff?
I am still not sure if I have a fuel delivery issue or an ignition issue.
I *think* the tank is a crankcase pressured tank, is there a fuel pump as well? An old hose with an airleak I assume could cause a fuel deliver issue.

Thanks for all the help getting my ski to 90%

Chris

[MA-Chris]

Forgot to add, I was also able to take the trim motor apart, with the help of Kano Kroil since it was corroded together and get that running again.

I sprayed CRC 6-56 in the motor and it loosened up immediately. Since these are plain bearing motors, I had no rusted ball bearings to deal with. Looks like I have a spare trim motor now.

[MA-Chris]

Alright, I may have figured out my hot start issue, the silly battery is not charging! I put a jumpstarter on it tonight and it fired right up.

What works?
Motor starts.
Trim motor works when the engine is running.
Fuel gauge works

This means the engine is generating power both a 12v for the trim motor and 5v for the fuel gauge.

I think this means both LR-52 and LR-21 are functioning as designed.

Is there a "wrong" way to install the orange/red-purple bypass? I am guessing there is a wire in the wrong place somewhere. So far, I put a multimeter on the battery when running and it was only 12.4v which makes me think it is not being charged.

How do I start troubleshooting this?