rotax 1503 2004 questions

[cykrus]

Hello guys,

I have just joined the team today I have bought a seadoo challenger 1996 with a modified engine, turbine, steering from rotax 1503 2004 (the 150 HP). For the past 2 weeks I have read forums and searched for tech stuff on these boats. I have visited a few 2 stroke engines but this one the 4 stroke I understand it is way better. On the digital speedometer it says the engine has 111 hours.

Now I have a few questions:

1. I have done a compression test and it is 180 on each cyl. Is this ok ?
2. How much is the consumption on this boat ?
3. How in this engine in terms of reliability ?
4. What to watch out fro this engine in order to keep it running ok ?

The guy I have bought the boat from was taking very good care of it, the engine is neat clean, he changed the oil 3 weeks ago. Anything else I should check before using the boat ?

Thank you,
Vlad

 

[ski-d00]

Compression is good. Fuel usage is not bad with that engine but don't expect it to be like a car. That is the most reliable seadoo engine ever made, imo. Not any real common failures with that motor, use good fuel, change oil and filter frequently and it should go to 400-500 hours without issue. 100 is pretty low for that motor but who knows if that is really true with a transplant like that.

Please post pics, I'd like to see it. Especially how it was mounted to the hull.

 

[devonte007]

Hi and welcome to the forum!

Let me get this straight, you have a 1996 challenger retrofitted with a 4tec 155hp engine and propulsion system? I have never seen one like that, I would love to see some pictures...

1. I think compression for the non supercharged 155hp engine should be closer to about 200psi, but not sure about that. Hopefully someone here with more knowledge can help with that one.

2. If you are asking about fuel economy, the 4tec 155hp is very good. As long as you are not riding around at wide open throttle all day, it is quite respectable.

3. The 155hp engine is one of the most reliable engines seadoo makes. If you drive it with sanity and do the proper maintenance it will last you for many years. Have heard these engines can easily make it past 900-1000 hours without any major rebuild. Not many known issues for faults with this engine.

4. Proper maintenance is necessary to keep this engine running smooth.
-frequent oil and filter changes with quality oil every 100hrs or at least once a season
-flush the exhaust cooling system well after any salt water use
-spark plugs with every oil change
-fog the engine when not used for a long period
-replace engine coolant every 2 years
-keep everything in the engine lubed and coated with a water displacing coating like wd-40.
-Inspect the jet pump every couple years to make sure bearings are greased and seals not leaking

Browse around the 4tec boat section and search for 'maintenance' and 'winterization' and you will find lots of posts with in depth information about detailed maintenance. Also download a PDF version of the shop manual from this site (find one for a 2004-2005 sportster 4tec) and read through it to familiarize yourself with the engine and mechanicals.

Sounds like you have a really neat and unique boat. Feel free to post back if you have any more specific questions. Probably should post in the '4tec boat' section to get the most help. Be sure to post some pics for us!

 

[cykrus]

Thank you for your answers. I took the boat to water yesterday for the first time (in Montreal on St Laurent river). GREAT ride.

I will post soon pictures of how the rotax 4tec engine has been fitted to this boat.

Now as I am a beginner i have a few more questions:

1. At 40 mph jumping thought small waves feel like the boat is constantly being hit with a big hammer ... I saw that this is the fun with this boat .. jumping though waves .. but my question is these hits on the water do they have any negative impact on the hull ?

2. On the portside the diver has the commands. I have 3 levers there ... The most left one is F N R, the middle on is the acceleration and then i have a small one. The guy who sold me the boat told me to have that one in front as i "take off" and then when the boat has speed to put it in the middle positions. Could someone explain me more scientifically what that lever is used for and how does it affect the ride ?

3. After i take the boat out of fresh water (it will only be used in fresh water) do i have to start the engine for the water in the exhaust to came out ? Do i have to do this each time ? For how long can i run the engine when outside of water ?

4. After riding in fresh water so I have to do any cleaning ? (you mentioned in one of the replies i have to do this in salt water ...)

5. Is it worth to install a depth finder on these type of boats (for security reasons) ? I read that there are some where the reader can be installed in the hull with epoxy. I dont want to drill any holes.

Thanks !

 

[devonte007]

1. these hulls are fairly shallow and not deep V, so they do not cut through big waves well as you have found out. As long as you haven't injured yourself or shattered your teeth, then hitting waves is probably not doing any damage to the boat. Probably not something you want to do all the time though....

2. Not really sure what that third lever does. Some boats and skis had a trim system for the jet pump nozzle so maybe that. When out of the water have someone move the lever and see what moves out in back of the boat or in the engine. Track down the cable and see what it is attached to. Since this boat is retrofitted it could be anything.

3. Normally the N/A 4tec engines are self draining for the exhaust cooling system which is the only thing that uses raw water to cool. Engine is cooled by regular green coolant and is closed loop. As long as the water is clean and fresh, then there is no real reason to flush it after use. I would still winterized that system by flushing it with non-toxic RV anti-freeze as part of the winterization process.

Without hooking the boat to the hose the engine should not be run for more than about 30 seconds, any longer that that and you risk melting the exhaust system. With the hose attached and water running you can run the engine for 2-3 minutes without any damage. If you do attach the hose perform these steps exactly:
a - start engine
b- turn on water
c- turn off water
d- kill engine

running water through the flush port at any time when the engine is off will flood the engine with water, and that would be really bad.

4. no real need to clean after riding, but always a good idea to wipe everything down. Try to get any dirt or scum off the boat and let things dry by opening it up for a while. Also a good idea to spray the engine compartment down with a water dispersing spray every now and again to keep things from corroding and generally dry.

5. depth gauge is up to you. Many people have installed them and I have even contemplated it at times. There are lots of threads about how to do it without drilling holes in the hull and using epoxy instead as you mentioned. It depends where you ride and if it is valuable to know your depth in unfamiliar areas. You can't go wrong either way...

 

[ski-d00]

third lever is VTS. you should push all the way forward to get fast starts and then back off to get faster speeds.

really would like to see pics, please post

 

[cykrus]

Here are the pictures. On the starboard side there is a charger for the battery, just plug it in and it can charge 2 batteries in the same time in case anyone asks. Now, at the jet pump i don't this it is visible but there is some fiber added there that is not part of the original hull.

I see what you mean by the 2 cooling systems i even see the coolant bottle. It's funny that after i take the boat out of water i open the 2 valves in the back of the hull and no water is commig out. i have tested a few 2 stoke engines and out of water at least 2-3 liters were coming out of there. Also on the dashboard there are 3 buttons .. the op one is the lights, the left one is the gas vent and the left one it does nothing. What was it supposed to do on the old engine ? The bilge pump is automatic so it is not that.

 

[ski-d00]

Very nice! Somebody put a lot of time into that and it looks like it was done very well.

The third switch is indeed the bilge pump. Even though it is automatic, it will also have a manual override switch.

 

[IDoSeaDoo]

OMG Someone beat me to it!!!

Here are the pictures. On the starboard side there is a charger for the battery, just plug it in and it can charge 2 batteries in the same time in case anyone asks. Now, at the jet pump i don't this it is visible but there is some fiber added there that is not part of the original hull.

I see what you mean by the 2 cooling systems i even see the coolant bottle. It's funny that after i take the boat out of water i open the 2 valves in the back of the hull and no water is commig out. i have tested a few 2 stoke engines and out of water at least 2-3 liters were coming out of there. Also on the dashboard there are 3 buttons .. the op one is the lights, the left one is the gas vent and the left one it does nothing. What was it supposed to do on the old engine ? The bilge pump is automatic so it is not that.


View attachment 27410View attachment 27411View attachment 27412View attachment 27413View attachment 27414View attachment 27415View attachment 27416View attachment 27417View attachment 27418View attachment 27419View attachment 27420View attachment 27421View attachment 27422View attachment 27422View attachment 27423View attachment 27424

Thanks for posting pics! I'm actually about to undertake this exact project myself! I absolutely LOVE this boat and hated the old 787 pos two-stroke that used to be in it. I already have the 4tec and have rebuilt it. Waiting to get a few more life-projects out of the way to start this. What kind of gas tank is in the boat? It seems that the stock one is not there. How many gallons does it hold? Also, it seems that he retained the original heat exchanger. Those black hoses coming out the back of the boat to the aluminum ride plate are actually what cools your engine. That ride plate has passages in it. When it's in the water, contact with the water takes heat away from the coolant, hence you can't run this boat out of water long, I would limit to a minute or so (or deftly listen for that overheat buzzer ). Wow, where did you even find this? Seems like the guy didn't cut up the hull to fit the propulsion system. I was planning on cutting out part of the donor ski and glass it onto the boat hull, but maybe that's not required. Could you send some better pics of the helm, I'll also have to fit in that sweet dash. Man, you have found yourself an AWESOME BOAT! I might have to hit you up for details as I go along with my project

 

[IDoSeaDoo]

Also, how fast does it go? Does your speedo work?

 

[cykrus]

Also, how fast does it go? Does your speedo work?

Hi there,

Yes i have realized this is a special boat from the moment i bought it. I have researches a lot before and seeing this custom project i was impressed (I am an engineer to and i understand the type of work needed to do something like this). Also the 4stroke easier to run than a 2stoke, i dont have to worry about the adding oil, the oil is kind of expensive, then the sound of the boat is different than the 2 strokes.

The speedometer on the boat i think has some problems ... both the digital and the analog one are showing a top speed of 55 km/h but i thought i was running faster. So i bought a few iphone gps apps that measure speed, distance etc and all of them showed me a 84km/h top speed when the dashboard was showing 55. This was on plain water, no wakes no wind, me alone in the boat (guess that was a small problem as the boat was tilted to the driver side and i weight 230 lbs). For me that speed is MORE THAN enough, i can even say it is not pleasant to ride at that speed.

As for the gas tank it holds ~45 liters, i dont know the brand, i'll look at the pump maybe it gives me a hint. I usually go around 30 km/h on the boat speedometer (so real about 45km/h) and one full tank lasts me 2 days of 4-5 hours/day on the lake.

Yes, the metal place is in fact a heat exchanges, this is what i thought about it and i have tested that one hose is warmer than the other (in and out).

As for the speed I don't know how much impact it has but the only thing i don't like how the guy did it is the exhaust pipe. He added a long (30cm long 2" wide) pipe with round exhaust nose toward the water. I guess that one created a brake effect on the water and also is the reason of the water spray I get on that side of the engine cover. I have seen that this type of boat does not need an exhaust pipe so long ... do you have any idea is i can cut it right after it exists the hull ?

The boat is in my garage right now winterized but if you need any detailed photos just ask the part you need in details and i'll send you

Vlad

 

[IDoSeaDoo]

You can cut the pipe off, but it will be louder. This engine is supposed to come with another exhaust resonator (not installed here) that makes it quite a bit more silent. The reason he angled it like that is so that it's submerged when you're at idle. You might get a headache listening to that drone if you're going for a slow cruise. What are those two switches left of the steering wheel? Those are definitely not stock.

The reason you have a different fuel tank is because the engine interferes with where the original tank would be. Could you take a picture of how far the engine goes under the seats? If he was to keep the original fuel tank, your hull would have to be extended. I was thinking of cutting mine and making it 10-15cm longer, but seeing how far your pump nozzle comes out, I am now thinking of doing it just like you have it. Could you also get a picture of how the driveshaft goes though the hull? No way that is stock. That driveshaft is 2 times thicker than the original, and the hole for it was about 8 centimeters too low. And the hood, I'm really curious how he got the gauges into the stock hood. Did he use fiberglass? Any chance you have the contact information of the guy that did this? I'd love to ask him some questions

 

[cykrus]

You can cut the pipe off, but it will be louder. This engine is supposed to come with another exhaust resonator (not installed here) that makes it quite a bit more silent. The reason he angled it like that is so that it's submerged when you're at idle. You might get a headache listening to that drone if you're going for a slow cruise. What are those two switches left of the steering wheel? Those are definitely not stock.

The reason you have a different fuel tank is because the engine interferes with where the original tank would be. Could you take a picture of how far the engine goes under the seats? If he was to keep the original fuel tank, your hull would have to be extended. I was thinking of cutting mine and making it 10-15cm longer, but seeing how far your pump nozzle comes out, I am now thinking of doing it just like you have it. Could you also get a picture of how the driveshaft goes though the hull? No way that is stock. That driveshaft is 2 times thicker than the original, and the hole for it was about 8 centimeters too low. And the hood, I'm really curious how he got the gauges into the stock hood. Did he use fiberglass? Any chance you have the contact information of the guy that did this? I'd love to ask him some questions

I understand the reason for the exhaust pipe now. I'll leave it like this. I will take the photos you wanted this week and post them here. On the lest of the steering wheel there are the 3 stock buttons (lights, bilge pump and engine vent) and the other part is the GTX buttons start/stop + mode + set (you can see it here http://www.ebay.com/itm/SEA-DOO-GTX-4-TEC-OEM-Stop-Start-Mode-Set-Switch-25B340J-/161147199039)

The hood, he used a part of metal to cover and some glue to fix the gauges. I will post a zoomed picture.

 

[cykrus]

another thing to notice is that with this setup he eliminated the engine cover because the coolant tank and gas tank are higher. I want to make another cover from fiber one that will adjust to the new shape for 2 reasons .. to be able to use the storage space and 2 to eliminate a little bit more noise. I have just bought a gopro camera and in spring I will post some videos of the boat on water, you will be able to hear and see it running.

 

[IDoSeaDoo]

No, I mean the other two, right next to the steering wheel. They look like rocker switches.

And yea, I noticed that you don't have a storage tray there. You can relocate the cooling tank to the front left side. There should already be some bolts sticking out where the old oil tank used to be. You could find the original tray that goes in there and modify it to accommodate the gas tank. The original tray has sound insulation on the bottom as well and is made of fiberglass: easy to modify. I noticed your name was Vlad, I speak Russian if that's easier for you

 

[cykrus]

Ah .. i see .. one of them is the radio switch and the other one the horn ...

In regards to the coolant tank, is there a rule on how low I can mount it ? Does it need to be above the engine highest point ?

Also as you seem to know a lot about seadoos, what is a good compression for this type of engine ? I have 180-185 on each cyl. Is that ok ?

My name is Vlad but I'm Romanian not Russian ... All I know in Russian is "davai pit piva" )

vlad

 

[IDoSeaDoo]

Haha, that is one of the MORE IMPORTANT phrasesof the Russian language.

Yes, that tank has to be higher than the engine. I'd say you can probably mount it as low as half way on the head, but if you mount it on just behind the seats, you could get it pretty high. That tank is slim and can go pretty much anywhere.

As for compression, your numbers sound good.

My radio is attached to a 850W Amplifier and has a 10 inch subwoofer The soundsystem is 10 times better than my car :thumbsup: There is a neat place where you can fit a 10 inch bazooka enclosed subwoofer in that boat. Let me know if you want more details