New guy, motor question

[avolnek]

Hey guys, this is my first post to this forum, have been lurking for quite some time however... I am not new to the world of engines and I have an electrical background, i have owned and repaired a number of jetskis but have never owned a boat until this year. My wife and I bought a 1995 Javelin fis/ski with a 1995 Evinrude 130 on it. When i bought it I had the owner meet me at a dealership for a tech to run over it with me as it was -2* out at the time. He was able to fire it up for me and ran it for quite a bit to verify it ran alright. He also did a compression test on it with me (all showed 130 +/- a couple)

I recently was able to get it out on the water. The motor starts great, Idles great but only provides a strong hole shot some of the time. It seems pretty doggy most of the time out of the hole. Once in a while launching out of the hole it will pin you in the seat and then sort of fall on it's face. Once it is planned out and running "full speed" it seems to only hit 4200 rpm and as soon as i touch the trim the motor coughs and bogs down, shortly after recovers and picks back up.

I can't tell if the motor is only reaching 4200rpm due to the trim being too low in the water and putting more load on the prop, i can't test it too well as when i touch the trim it coughs... but i assume it will reach higher. just operating the throttle i can get it to reach nearly 6,000rpm. I also noted that when you would hit the trim button (any of the button locations caused this issue as well) that the tach needle would deflect slightly.

In the driveway last night i ran it and was watching my battery voltage. prior to start it was somthing like 12.8v, at an idle was fairly similar and slowly climbed with rpm. at around 3,000 rpm it was up to nearly 16v.

I have since dug into the rectifier as it seems to be an issue that comes up a lot. (side note the ignition was power pack was replaced last year by dealer) I did note that one of the legs of the rectifier was acting differently from the others. I probed it many ways with the diode test on my meter. Off hand i remember that two of the three legs had no reading either way when i probed the wire and the case of the rectifier, while the other leg provided a reading each way i believe...

Any insight from you guys would be greatly appreciated. I hate to just throw parts at it, but i do believe if the rectifier is bad and feel it needs replaced regardless, but i am unsure if that is the only issue at hand.

 

[avolnek]

A quick update.

I ohm's both batt cables to the motor, both have very minimal resistance.

I had both batteries i have used while testing loaded tested and both tested good.

I did order a rectifier and will update once i can get that installed.

my only other possible is poor positive connections. I will be pulling them all apart throughout the night/week and cleaning... hopefully can find something simple...

sort of thinking out loud here, but i am not sure if the rectifier would have much impact on the issue at hand or not as i am aware that the stator should support the ignition side of things completely independently of the battery and charging side of things... but at the same time maybe the added load of the trim motor and overcoming what the rectifier is putting back out and in return bogging down on the stator... ?

 

[F_R]

The motor generates it's own, separate power to run the ignition system. The ignition system is not powered by the battery. In fact it would run with no battery at all (but would blow the rectifier if you were to try doing that). The rectifier is for charging the battery only, has no effect on the ignition system or performance. If it was putting out 16V it was working normally. Unless you blew it while messing with it.

I'd suggest you check the throttle/spark advance lever. It may be sticking and opening the carburetors before the timer is at full advance. Just a guess.

 

[avolnek]

That could explain some of the hole shot issue, but doesn't really touch much of the motor hesitating when operating the trim switch...

i will take a look at the spark advance though as well...

 

[gm280]

:welcome: avolnek, to iboat...

Your engine has both a rectifier and a regulator. So if you are reading 16 volts, I would say the regulator is bad. Then you have a power pack, stator coil, timer base and sensor assembly. So any of them can cause issues. Have to checked the battery voltage when you press the trim switch? I would be curious to see what the voltage was during that time. Seem there is a connection between the trim switch and the engine. So you really need to see how the voltage checks when using the trim. Could be the trim motor is partially shorted or consuming more current then it is supposed to and therefore dropping the battery voltage. Post those results for us to help you out. JMHO!

 

[avolnek]

Yes, when operating the trim motor up or down I can get the voltage at the battery to drop roughly a full volt to 11.8v. Usually though it is more common for me to see .5v drop going down to low 12v. These are with the engine off. Seemed to show the results while running. Could drop roughly a full volt bumping the switch repeatedly with the engine running.

Any other insight would be great.

When testing my rectifier I probed off of the ac input lines to the three dc outputs. Only one of the leads showed any continuity via this test... It doesn't appear to be correct to me but I'm not so sure it's the solution to the problem either...

 

[flyingscott]

Why do you think it's an electrical problem, try this when you are running have somebody pump the fuel ball see what happens to rule the fuel pump out. Next go buy the factory service manual or go to www.cdielectronics.com they will tell you how to test your electrical system.

 

[avolnek]

Assuming it's electrical is straight up assumption.

I also assume the fuel pump was mechanical, which I just now see as that not being true...

I have a manual and it appears that things ohm out with in reason, minus the rectifier. The manual tells me to test it via amp readings and with my electrical background I've been taught to test with the diode function on my meter. Per that test I don't like what I see from the rectifier.

However looking at the fuel pump appears to be worth while.

 

[gm280]

Assuming it's electrical is straight up assumption.

I also assume the fuel pump was mechanical, which I just now see as that not being true...

I have a manual and it appears that things ohm out with in reason, minus the rectifier. The manual tells me to test it via amp readings and with my electrical background I've been taught to test with the diode function on my meter. Per that test I don't like what I see from the rectifier.

However looking at the fuel pump appears to be worth while.

I am not saying you don't have a fuel pump issue, I honestly don't know. But what bugs me is your engine stumbles when you touch the trim function switch. So there is something that deals with the switch and the engine performance. I don't see that as a fuel delivery issue. I mean the carb(s) should be holding enough fuel that even if the fuel pump were to stop when you push the trim switch, there should not be an instant stumble. So I am leaning towards an ignition problem from the info provided. JMHO!

 

[avolnek]

I am not saying you don't have a fuel pump issue, I honestly don't know. But what bugs me is your engine stumbles when you touch the trim function switch. So there is something that deals with the switch and the engine performance. I don't see that as a fuel delivery issue. I mean the carb(s) should be holding enough fuel that even if the fuel pump were to stop when you push the trim switch, there should not be an instant stumble. So I am leaning towards an ignition problem from the info provided. JMHO!

That was my thought process as well.

Looking at the pump as you mentioned, two of the three dc outputs off the rectifier go directly down to the fuel pump. The third is connected to the battery side of the starting solenoid to charge the battery.

Seeming more like the regulator finding that tid bit.


Thinking out loud...

However like mentioned the ignition SHOULD be completely independent of the 12v side of things that would theoretically eliminate the rectifier as being the problem. However the only real relation between the ignition and the trim motor would be the rectifier or a short, which I don't seem to find...

 

[racerone]

The factory fuel pump on that motor is operated by crankcase pressure.-The wires to the factory pump are for the alarms on that pump.

 

[avolnek]

The factory fuel pump on that motor is operated by crankcase pressure.-The wires to the factory pump are for the alarms on that pump.

Well that sorta killed my mood... Guess I will just have to see what the new rectifier does for it...

I would greatly appreciate anything else to look for though.

 

[flyingscott]

Low fuel pressure will cause the problem you are having. Check the ignition side of the stator not the charging side. Does the tach on your motor still work first sign of a failed rectifier is the tach stops working.

 

[avolnek]

Low fuel pressure will cause the problem you are having. Check the ignition side of the stator not the charging side. Does the tach on your motor still work first sign of a failed rectifier is the tach stops working.

Yes the tach still works, but it does deflect slightly when the trim switch is bumped.

As far as the ignition side of the stator I did check it, I forget the exact number, I will post them shortly but I do believe it was a bit out of tolerance per my manual.

 

[emdsapmgr]

Possible you have intermittent spark to one plug. Weak ignition components tend to fail, once the engine heats up to "normal" operating temps. May run fine when cold, then be sluggish when it warms up.

 

[avolnek]

Okay, the manual calls for the charge coil to be 480 +/- 50 ohms. I measure it to be 394 ohms, so just a bit out of spec.

The power coil which feeds the rectifier is specd to read 96 +/- 10 ohms. I read 92.8 ohms.

 

[avolnek]

Okay, staring at it some more my stator has three circuits in itself it appears. Two of which run straight to the power pack for ignition and the other goes to my rectifier.

The one going to my rectifier ( yellow wire and yellow and gray wire) ohm to be 1 ohm. I cannot seem to find what this is supposed to be in my manual...

In theory the less resistance to the winding would mean higher voltages coming out with decreases amperages.

So is it possible that this is supplying enough of a voltage to show a charge but not enough to really support it. Ie when the trim is engaged the engine falls on its face?

 

[avolnek]

read a good suggestion today from another thread. It was suggested to unplug the trim harness leading to the boat leaving only the trim switch directly on the motor attached.

Once my new rectifier gets here I will test it and verify whether or not it tests the same way my current one does to see if it is bad. I will get it installed and running in the driveway and if that doesnt fix it I will try that test of unplugging the boat side of the trim switches to see if there may be a short somewhere. Would make sense that there could be...

 

[avolnek]

Well after relocating the rectifier and the battery with a pure cranking battery the issue of the engine cutting out while pressing the trim switch has been resolved.

I do however still have a miss right at 3700 rpm. Sometimes it will power right through it but some times it seems to get hung up and miss right there. When it does power through it runs great up to around 5500 rpm but when I bring the throttle back it begins to miss right at 3700...

The shop manual tells me to check the charge voltage to the each of the plugs under load, which I am unable to do. As well as refers back to test the "slow" function which limits the motor down to 2500 rpm. The miss does sort of sound like I'm hitting a rev limiter but really doesn't at the same time...

Thoughts?

I ohm'd the timer coils and they are all in spec. My charge coil says it should be 480 ohms +/- 50. And I'm just under at 380. Doesn't make sense that this bit out of spec would only affect a certain rpm area.