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seadoosnipe
06-04-08, 11:03 PM
There have been quite a few members asking about the safety of jump starting your ski/boat. While its not common practice to do this, there are times when you may get stranded and find there is no other choice. To jump for that purpose is o.k, but if you have a bad battery and jump it continously, just so the charging system will run the electronics of the ski, eventually, you will burn up your regulator.

To jump a battery, follow carefully. The vehicle (boat, car, tractor, helicopter) your starting from, must be a 12 volt DC (direct current) battery. This vehicle must not be running. Attach the jumper cables to that vehicle. Then, attach the positive to your ski/boat battery. Then, attach the ground to the engine block, preferably to the grounding lug at the engine, coming from your battery. This will keep a spark from arcing to your positive post and creating explosive conditions.

What the "superstition" is all about with this procedure, is that if the vehicle your starting from is running and you connect cables to it, your not sending 12 volts to your battery and electrical system, your sending anywhere from 13.5 to 14 volts. This may cause you to overload and short your electronic control module or mpem.

It's best to have a jump box available or if you own a boat, put a second battery in dedicated to your accessories, so that you won't run down your primary battery. You will need to use a switch to isolate your battery when the engine is off. Here is a link to the switch you see in most boat applications. http://www.boatmartusa.com/marinemall/perko-battery-switch-with-field-disconnect-p-433.html?currency=USD

Remember, a jump is normally used for emergency situations. Don't do it habitually, you may damage your rectifier/regulator.

ROC 87
06-13-08, 06:50 PM
I have a friend that used cables to jump his 96 GTS ski.(I not sure(doubt)he followed your advise) Now as soon as you connect the battery it blows the 5amp fuse in the electrical box. Do you have any ideas of the problem or advice as to what to check and how. Thanks

seadoosnipe
06-23-08, 08:36 PM
Well, that doesn't sound to good, sounds like he's damaged the MPEM.

But, there is good news. Rather than replace it, there is a member in the forum, All Things Custom, who works on these things. Seems he's found a way to fix mpem's that constantly blow their fuse.

Heres a link to his buy/sell/trade add..........http://www.seadooforum.com/showthread.php?t=2254

You may want to click on his ebay link. I haven't seen him in the forum in a while. I think he does small engine repair work from his garage and is swamped. I spoke to him by phone a couple months or so, said he was swamped.

Give him a try. I think if he can fix it, it's about $100 bucks, verses the replacement cost.......:cheers:

All Things Custom
07-16-08, 03:25 PM
:agree: LOL

What he said... Never ever ever... jumpstart a seadoo ski.

It blows a circuit in the MPEM that I do repair, so if you want to pay for a new MPEM or pay me $140.00 with shipping go ahead. ( I do need to make a living you know)

Seadoo knew this back in 1989 when they produced their MPEM and the fix they had was to stick a sticker in the hull that says something like Dont jump battery while in ski.... rather than fixing theier design flaw. :)

Johnson8537
08-09-08, 04:58 PM
Just curious does your FIX also fix seadoo design flaw???

wryirshwit
08-13-08, 11:19 PM
you can do a quick jump with another PWC, car or boat just do it quick burst not long burst on the starter. to get it going or you will fry your starter. don't do it to often or you will fry your starter. just incase battery is dead for emergency.

seadoosnipe
08-19-08, 09:55 PM
You can only jump in this manner as long as the engine from the vehicle your jumping from is turned off.........

If you read the first post, it's not about the starter getting hot, it's all about the voltage from a running vehicle. When your 12 vdc system is running, their is between 13.5 and 14 vdc being generated....but at the mpem, it's only using 12 of those volts........If you jump from a battery with 14, you endanger blowing the mpem..........plain and simple. It's not about the starter.:cheers:

shootawave
09-02-08, 01:47 PM
Above all the previous postings as first stated! Please let the engine compartment air out completely first! This is a confined space that will keep the potential Volatile gas compounds in the hull, thus creating an explosive atmosphere. If it blows up, it wont be a fun day......Stay safe always please!

seadoosnipe
09-07-08, 12:57 AM
Being safe is always paramount, but if you have a ski or boat that has built up enough parts per million of fuel vapor, to ignite while jump starting and you can't smell it...........:cheers:

timmyboy76
09-07-08, 01:05 AM
what, in other words..dont jump start with a "cold"...:rofl:

shootawave
09-08-08, 05:48 PM
EXACTLY Guys! You would be amazed that it can be a thin line on the PPM's I have seen enough of the aftermath personaly and its not pretty. A lot of the general public just dont know about vapours, flashpoints or voc's (volatile organic compounds) Just a quick word of caution!!! and yes i like the cold part too.. use someone elses nose or a gas meter Thanks guys.

popasodatastie
01-22-09, 10:49 AM
would it work to jump start a jet ski with another jet ski battery or is that still not adviseable?

rippinsurf
03-22-09, 03:39 AM
sorry to keep the changed subject going but ive noticed a very nice spark shooting from my starter because the starter cable cant be tightend all the way cause the stud is broken or loose in the starter... i wasnt worried about it cause it starts jus fine and never acts like it dont want to... but now youve got me scared ima go start it one day and BAM! ZING! ZOOM! RIGHT TO THE MOON! that would SUCK!!! ive no fuel leaks but you never know one day huh... perhaps jus letting it air before each start would be good huh.. or even jus taking the seat off... hell i could deal with a flame but a bomb would suck haha.

seadoosnipe
03-22-09, 01:34 PM
There is a sticky in the forum on jump starting. If you have to do it, use one of the jump packs or from anohter vehicle, with the engine off. The issue with jumping from a car or other vehicle while running is the other vehicles charging system coming into contact with yours. The battery is designed to start at 12 VDC, not from 14 VDC that is being supplied from an outside source....

As for the spark at the starter, .....this is likely a loose connection or bad wire. This needs to be troubleshooted and found ASAP. This type short can cause you to short out the MPEM. Then, you'll be replacing a lot more than a stud on a starter!.........:ack:

mojo0107
05-12-09, 11:20 AM
I think that is how I fried the VTS fuse on my old ride... I put an all new vts system in it cuz the stealersip told me too...and it was a fuse. LOL. I hate them... I've seen PWC's w/ a second battery, that was hooked up to the charger that only ran a radio/mp3 player, it would discharge only the radio battery and not the engine one. Is this ok on the ride and how hard is it to do this?

Chris_cox
05-12-09, 11:49 AM
you can wire it so that the 2nd battery is charged with the oem battery but only powers accesories

05GTXSC
06-11-09, 10:34 PM
Is it OK to have a trickle charger on it while it is still hooked up?

captainjack987
06-17-09, 01:47 PM
yes it is fine. In my experience marine batteries arnt of the highest quality and i find replacing them every season is a good bet to keep everything predictable.

BillinNH
06-24-09, 02:23 AM
My experience with my 11 year old GTI is if I get 3 seasons out of a battery, it was a good battery. Our season is short and I keep mine on a trickle charge, and in a heated basement over the winter. The one I have is 3 years old now so I'm going to replace it as a matter of course when I put it in the water this weekend.

CragarShinoda
08-09-09, 03:26 PM
Why jump your boat or PWC off anyway? Just roll it off. lol I kid, I kid!:rofl:

orbital02
08-11-09, 01:00 PM
This is probably going to sound dumb but I did what the first post said NOT to do. I hooked up my truck to jump my battery with it on twice. I must have got lucky the first time, but after the second it started and ran for about 200 yds. before it bogged down and died. I checked the fuses and the only one blown was some 7.5 amp fuse (anyone know what that one goes to?) The other thing I noticed was it now won't get spark at all. It turns over fine, but no spark. Any help would be appreciated.

larrylongboat
08-16-09, 02:33 AM
bad battery and jump it continously, just so the charging system will run the electronics of the ski, eventually, you will burn up your regulator.

To jump a battery, follow carefully. The vehicle (boat, car, tractor, helicopter) your starting from, must be a 12 volt DC (direct current) battery. This vehicle must not be running. Attach the jumper cables to that vehicle. Then, attach the positive to your ski/boat battery. Then, attach the ground to the engine block, preferably to the grounding lug at the engine, coming from your battery. This will keep a spark from arcing to your positive post and creating explosive conditions.

What the "superstition" is all about with this procedure, is that if the vehicle your starting from is running and you connect cables to it, your not sending 12 volts to your battery and electrical system, your sending anywhere from 13.5 to 14 volts. This may cause you to overload and short your electronic control module or mpem.

It's best to have a jump box available or if you own a boat, put a second battery in dedicated to your accessories, so that you won't run down your primary battery. You will need to use a switch to isolate your battery when the engine is off. Here is a link to the switch you see in most boat applications. http://www.boatmartusa.com/marinemall/perko-battery-switch-with-field-disconnect-p-433.html?currency=USD

Remember, a jump is normally used for emergency situations. Don't do it habitually, you may damage your rectifier/regulator.[/QUOTE]

RustyStunts
09-11-09, 11:21 PM
good s***? ride on!

seadoosnipe
09-12-09, 04:59 PM
This has always been a topic of interest to our members. We are so used to just jumping off our cars when our battery is dead. But, with the PWC's or jet boats, you take a risk in damaging your MPEM or ECU. These electrical units are very expensive to replace so I would always caution against' doing it.

You can jump from another battery, only if the one you are jumping from is shut down or their alternator is unpluged. It's the charging system of the other vehicle, no matter is it's a car, boat train or plane, you need to isolate the charging systems.............:cheers:

heythere152
09-20-09, 03:33 PM
i have a 98 gsx. my battery just died, should i disconnect the positive cable and charge that way or neg cable removed . all skis are 12 volt correct?

timmyboy76
09-20-09, 05:35 PM
i'd remove it from the ski, and charge.

mudpie
11-04-09, 08:31 AM
first off, i am new to this forum, so hello all!
second i work on these things all the time , sigh!
third , i have jump started hundreds,yes hundreds of skis with no ill effects!
yes you must NOT have jumping vehicle running !!!!!
voltage is one issuse but amps is the killer!!!
most cars put out over 80 amps from alternator
ski is rated at 30 amps
as for the 5 amp mpem fuse, the mpem can go bad, its a fact of life
like light bulbs,tvs,anything else, it can break!!
simple way to check is to just unplugged everthing else from mpem and then just give it a power and ground, if fuse pops, bad mpem.
as for the 7.5 vts fuse, water intrusion thru vts rod shaft is what i think
the boot at rear of boat becomes brittle and or the metal hose clamps cut into it, allowing water to travel into the sealed!! vts housing were it does its damage, thats why brp started using those little nylon clamps.
and as for mpem only seeing 12 volts while running, hmmmmm????
not sure if that theroy is correct, i would think that it would see battery voltage all the time 12.5 at start up and up too 14.5 at wfo
will have to check this for my self
regulator/rectifiers go bad all the time, but with some help from the owners!
keep you batt terminals clean and tight!!!!
have seen a reg/rect go bad and over charge a ski, this caused the thing to act like the rev limiter was hitting at 4 k rpm, gues it was making the mpem go nutty.
put new one in and it ran great
mud


This post was originally disapproved because I mis-read his comments. I read into his post that he said "to jump start with a running vehicle". Upon reading it again, I see I mis-read his post. The other specific point is the 12 volts at the mpem. This is true but the mpem breaks down the voltage to 5 vdc for use in your instruments.

Sorry for the mis-understanding. Your info is correct and it was my mis-reading it that caused me to un-approve the post.

Thanks for PM'ing me to bring this to my attention. This is how we solve issues when there is reason for debate.

Welcome to the forum and thanks for helping out with members problems.

jackson09
11-04-09, 11:23 AM
i jumped my first ski before and then the starter fried too the brushes melted, maybe from a combination of cranking and jumping

greyrider
11-04-09, 12:38 PM
would this apply to those portable 'jump starters' that put out mega-amps as well?

when i sunk my ski and had no idea what to do a local guy pulled plugs and went through the hydrolocked procedure. he was a kawasaki guy and jumped mine from a pickup truck while running - it runs fine - guess i got lucky?

mudpie
11-05-09, 07:06 AM
jump boxes are fine, the ski will draw the amps from the box that it needs to crank! battery chargers tho, the ones that have a 2amp, 10 amp charge and then a 50 amp start postion is bad, very bad for smaller vehichles, skis, bikes, atv's ect.
as for the previous post with the fried starter, excessive cranking can cook a starter and or starter solenoid.
other things that can lead to this is siezing pump or engine, water in engine.
what happens is someone will think that the battery is low,cause the engine is cranking slow or wont turn at all cause something is stuck.
they grab a boost box and keep cranking on the poor thing,till the starter or solenoid fails, sometimes they will stick and keep on cranking till the battery dies.
mud

seadoosnipe
11-05-09, 07:33 PM
would this apply to those portable 'jump starters' that put out mega-amps as well?

when i sunk my ski and had no idea what to do a local guy pulled plugs and went through the hydrolocked procedure. he was a kawasaki guy and jumped mine from a pickup truck while running - it runs fine - guess i got lucky?

This thread has been gone over throughly. It was meant as a guideline for jumping your ski, according to BRP's recommendations.


To answer your question Greyrider, no, it does not apply to jump boxes. I don't remember what post number this is, but it's up there. If you go through this entire thread, you will see that it's already stated that the jump boxes are fine. It's also stated that the reason why you do not jump start with a running vehicle is because of the "possibility" (key word, possibility) that you might do permanent damage to your electrical system. When jumping from another vehicle that is running, there charging system is in operation. Which means, the battery is receiving 14 VDC. When you jump start from that system and your engine starts, you have 2 different type charging systems grounding to each other.

This does not mean that your MPEM or rectifier is "going" to blow, it simply means that you are taking a chance. With the price of our MPEM's in the hundreads, if not thousands of dollars, I would think it's better to take preventitve action than it is to take the chance.

As with overheating the starter, melting wires. This is true with anything that has a starter. The starter draws 90% of the batteries CCA (cold cranking amps) during initial startup. The starter is a high torque motor and has to overcome the engines compression to turn the crankshaft over. According to BRP and stated in the shop manual, you should only turn your starter over for 30 second intervals. If your troubleshooting or having a hard time starting, grab your ground wire and see how hot it is. If your battery cable wires are getting hot, shut down the engine and let the system rest.

My advice:...Never, Never, Never jump start a Rotax engine with a battery from a running engine. Did, I say Never?...Just checking. You may be lucky several times but eventually, your going to be paying for a new MPEM. You got $500 bucks. Then feel free to take that chance.

With this being an informational thread I put together some time ago, as a guide to jump starting, I did not intend for it to go on as far as it has. Most threads I do as guidelines, I usuallly I close them because it's nothing I'm looking to set up for debate. This thread, I just didn't close it. I am going to open it back up because it seems, many members would like to add their own experience.:cheers:

luckysaturn13
03-16-10, 06:10 PM
are the fuzes in the gray box by the motor or the gray box off to the left side? I bought my ski used non running he said ran for a bit died and had to get it towed in. said he hasnt ran since.I wonder if he used a running car to jump. I didnt ask. :( Im doing the normal routine mataince,filters,plugs, fuel lines, and carb rebuild and a brand new battery then going to investigate. I hope its because of something i already listed. The battery in there was like 5 years old and wouldnt hold a charge. If it dont run right when i get it back together im going to investigate rectifier check for spark and voltage stuff. Any tips? also how do i diagnose if he jumped and fried it? Is it Just the 5 amp fuse will keep blowing ? will it still crank over and stuff just not run right?

thanks.

jay64
06-11-10, 11:32 AM
Is there a way to test the MPEM or the ECU to see if either of these has gone bad?

Rojoyinc
08-05-11, 12:26 PM
I didn't read this before jumping my Speedster via jump start battery. I have used it about 3 times and I had a fire start in the boat... my voltage regular caught on fire while towing a skiier. Luckily - boat is ok, but is now in the shop (several hundred I'm sure... as quote to start was 380+.

voltage regular melted and all wires connected. Take this warning above seriously.
I wish I had seen it before.