First Boat, first boat issue...

[Etech331]

I purchased a 2004 Sea-doo Sportster, 947 Rotax direct injection engine, 2 cylinder . Ran it for an hour just me and the wife. Basically putting it threw its paces. one week later I filled up with regular gas approx. 40 litres, (89 octane with up to 10%ethonol), topped up the oil with a litre of TC-W3 Synthetic blend oil, and ran the boat for an hour and half towed the kids on a tube for an hour of it. on our way in it was not quite running as smooth as it had up to then. A week later filled it up again about 40 litres same gas, dropped it in the water it would start but would stall as soon as I put in either forward or reverse. opened the back checked the plugs and they were black and sooty sort of, wiped them and put them back in. still would stall. got it back on the trailer and out. This is my first boat, I was an electrician for thirty years but as a mechanic I am just an apprentice. I am looking for some advice as to where to start if new plugs don't fix the stalling equation.

 

[14SX190]

Hi and welcome.

Those 941 Sea doo engines are a ticking time bomb.
They are the highest hp 2 stroke engine they made back in the day and are very picky.

I would suggest looking at fuel lines. If they are grey, they need replacing. Also, the carburetors should be taken apart and cleaned as a lean condition with cause engine to detonate. You could check compression and see where your at.

Also, you may want to change oil to the API-TC vs TC-3.

Check out this site for all things Sea doo
Seadooforum.com

Their are people there that can help you with carb rebuilds or parts needed.

 

[Beachbummer]

Yes, that's not the right oil for that boat. API-TC with Low Ash is what you want. Look for PWC Oil, NOT TWC-3

But in my experience 90% of the problems with these boats are the carbs. pour a little gas or starter fluid to troubleshoot the carbs out of the equation. (Only if new plugs don't fix it. If they looked bad, that may be the only problem)

 

[14SX190]

Yes, that's not the right oil for that boat. API-TC with Low Ash is what you want. Look for PWC Oil, NOT TWC-3

But in my experience 90% of the problems with these boats are the carbs. pour a little gas or starter fluid to troubleshoot the carbs out of the equation. (Only if new plugs don't fix it. If they looked bad, that may be the only problem)

Check the fuel selector while your at it?
If fuel lines were/are grey there is a good chance selector is clogged.

Also, carb has little internal filter that could be clogged as well, hence the need to rebuild them if that is your problem.

Best thing about 2 stroke is it simplicity Air-->Fuel-->Spark-->Boom.

Pics stolen from:

Troubleshoot Fuel Delivery Problems : low revs, bogging, surging

Do you have any of these symptoms on your carbureted 2-stroke engine? :confused: - Low revs in water with throttle all the way on - Okay revs out of water, but low revs in water - Bogging when going from idle to full throttle - Surging of revs - Intermittent or sudden cutting out of engine...

www.seadooforum.com

 

[Etech331]

Thanks to both of you, I will have to get a little more serious with this boat ownership life that we have entered into. @14SX190, @Beachbummer, your advise is now noted and I will let you know what I find out. Its funny that you mentioned the internal Fuel filter as I was unable to find one as I wanted to replace that after the plugs.

 

[Beachbummer]

My SeaDoo experience is with the 717 engine, so you engine minus 2 or 3 revisions and sizes. Now you mentioned 947 "Direct Injection" this one does NOT have a carburetor, as it is a direct injected engine, so our Carb and Carb filter suggestion is misplaced.

I Would suggest switching to the right oil (maybe even removing whatever is left from the one in the tank) and with new plugs hopefully you are good to go.

Long term you can try to find the fuel pump and if possible add a spin on fuel filter/water separator before it. They are cheap and very effective at cleaning the fuel the engine receives.

Best of Luck!

 

[14SX190]

My SeaDoo experience is with the 717 engine, so you engine minus 2 or 3 revisions and sizes. Now you mentioned 947 "Direct Injection" this one does NOT have a carburetor, as it is a direct injected engine, so our Carb and Carb filter suggestion is misplaced.

I Would suggest switching to the right oil (maybe even removing whatever is left from the one in the tank) and with new plugs hopefully you are good to go.

Long term you can try to find the fuel pump and if possible add a spin on fuel filter/water separator before it. They are cheap and very effective at cleaning the fuel the engine receives.

Best of Luck!

Me too. That engine was a work horse and simple compared to the 787 and 951
I should of caught you were talking about the DI one. My apologies.

Compression check would be first on my list as there is no sense in problem solving an engine with no compression.

Keep us posted.

 

[Etech331]

An update to my earlier post... I replaced the plugs and it seemed to be the fix. We ran the boat through it paces for about a half hour and then docked it without incident. Came back out this weekend and ran it for about 40 minutes without problems (avg about 4500-6500 rpm) but then it started to lose power. I jumped in thinking that we had sucked some weeds as we had traveled through some shallow water. Managed to pull some out but it didn't seem as much as it should have for the engine to lose so much power. I started the boat up again and now it couldn't move then boat faster then dead slow without excessive exhaust. I checked the plugs and they seemed not that bad but there was some wetness to them. I am now attempting to find someone with the right diagnostic tool. Certainly sounds like a lack of compression.

 

[14SX190]

Where you located? May be som one close can give you a hand.
Compression check would be first step for sure.

If that checks out check the pump as they have a plastic liner that when damaged will give you no thrust and engine will just redline

 

[Etech331]

I am in the Ottawa, ON, Canada region. Pump? What pump are you speaking about? I am just now trying to find an online owners manual.

 

[14SX190]

Yeah that is a little far or me.

The pump is where the water exits. Sea doo has a plastic ring surrounding impeller that gets chewed up and is a "wearable" part hence name wear ring.

Depending if during your first or second outing you sucked up something it could of damaged it.
If you look down pump or under boat through intake grate and see white or chunks of wear ring missing could explain lack of acceleration.
Turn volume off and skip to 6:00 to see removal of ring

Most Sea doo's with low compression won't start in the water. They will smoke though. A lot depending if boat is not on oil injection which I think you are but should drain that TCW and re fill with the API-TC as the two sometimes does not mix.

 

[14SX190]

I am in the Ottawa, ON, Canada region. Pump? What pump are you speaking about? I am just now trying to find an online owners manual.

manuals

There you go

 

[Cobra Jet Steering LLC]

Direct injection it has fuel injectors , and oil injectors starving for AIR or too much fuel same result cold engines run good with lots of fuel but warm they will not run very well so It is a fuel issue