Question about 4 stroke motor compression...

[Nosnibor]

Hello,

I joined the forum last year trying to get some info about owning a jet boat. I do not own one yet but I hope to by this season. After waiting from pulling the trigger last year I decided it would be worth it to go with the newer 4 stroke motors. I remember when talking with others in the 2 stroke section that compression is very important when buying a used boat. It basically tells you if the motor is good or not (from what I gathered).

I was wondering if this is true for 4 stroke motors as well and if the numbers differ at all? I'm still very new to this and I just want to make sure I get the best I possibly can for what I'm paying.

Thanks!

 

[Coastiejoe]

It is true in that it will tell you the basic internal condition of the engine. 4-tec engines are MUCH more expensive to repair/rebuild, so you really do need to start with a good base...

On the flip side, the 4-tec engine can run for thousands of hours. I have two of them and love them both...

 

[Nosnibor]

Thanks for the info. I know everyone says "bust out another thousand" but I would at least like to find a boat that can get me a few seasons of fun before anything major. So not being so mechanically inclined I want to know what I can before making a big decision.

 

[xintersecty]

Depends on your budget, yadda yadda yadda. The four stroke motors have two major issue: ceramic washers in the supercharger and a sodium filled valve that breaks. I personally have two of those motors in those years with those issues. Somebody else can give you the specifics. So when looking at used boat, you will have to check both of those conditions. I know the supercharger for my boat has the metal washers, I don't know for my RXT. I am going to pull the charger when I change the oil.

Personally I love my jet boat, I love the sound, I love the way it moves. And besides they are actually easy to work on.

 

[Coastiejoe]

Just post what you are looking at and we can tell you about the week links if there are any..

 

[Nosnibor]

Thanks for that info. Is that stuff I am going to be able to check without taking into a shop first? Seems like it may be difficult to verify those things. Also you said you have metal washes. Did you do that yourself?

 

[Nosnibor]

I have looked at a few but I am liking this one as of now. Mainly because it isn't yellow and because it comes with hydro-turf already and I was planning on changing speakers in the future anyway. I don't understand what he means by the arm rest but he is going to be sending me more pictures.

http://norfolk.craigslist.org/boa/4966431582.html

 

[DLB]

I have looked at a few but I am liking this one as of now. Mainly because it isn't yellow and because it comes with hydro-turf already and I was planning on changing speakers in the future anyway. I don't understand what he means by the arm rest but he is going to be sending me more pictures.

http://norfolk.craigslist.org/boa/4966431582.html

boat looks nice but seems overpriced to me. good thing about an 08 is that you dont have to worry about the hollow valves. the supercharger shouldn't have the ceramic washers by 08 either.

armrest.. i think he is talking about #6 ELBOWREST ASS'Y part#204614429 $39.99 ... http://partsfinder.onlinemicrofiche...=seadoojb&a=43&b=22&c=0&d=-HULL---ACCESSORIES

 

[Nosnibor]

boat looks nice but seems overpriced to me. good thing about an 08 is that you dont have to worry about the hollow valves. the supercharger shouldn't have the ceramic washers by 08 either.

armrest.. i think he is talking about #6 ELBOWREST ASS'Y part#204614429 $39.99 ... http://partsfinder.onlinemicrofiche...=seadoojb&a=43&b=22&c=0&d=-HULL---ACCESSORIES

Yeah I don't know really about the pricing for them. Everything seems to be in the mid 12-15k range for boats with double or triple the hours.

 

[DLB]

NADA can give you an idea of price. http://www.nadaguides.com/Boats/2008/Sea-Doo-BRP/150-SPEEDSTER-W-TWR_/10256410/values.

 

[Nosnibor]

NADA can give you an idea of price. http://www.nadaguides.com/Boats/2008/Sea-Doo-BRP/150-SPEEDSTER-W-TWR_/10256410/values.

I just read the thread a few post down about the guy with the 50 hour 2006 and his middle piston blew up. Should that be something I should be concerned about here with the boat not being used all that much (if really only 30 hours)? Also the thing about the 100 hours/ 2 year super charger replace. I'm assuming this would mean I should look at a rebuilt super charger right off the back if I were to get something like this?

 

[Nosnibor]

NADA can give you an idea of price. http://www.nadaguides.com/Boats/2008/Sea-Doo-BRP/150-SPEEDSTER-W-TWR_/10256410/values.

Also that NADA is for a 2008 150 not SC. I looked up the 2009 with the SC and average was around 11,060.

 

[DLB]

the Craigslist link you posted was for an 08. the NADA link i gave was for the 215HP it just doesnt say it on that page. i would have the SC rebuilt.

 

[DLB]

oops. my mistake. i did give wrong NADA link. Avg Retail $11000 it shows but I think I would want to be under $10K. things may be different where your at but down here in FL there are lots of them around for sale.

 

[Coastiejoe]

I just read the thread a few post down about the guy with the 50 hour 2006 and his middle piston blew up. Should that be something I should be concerned about here with the boat not being used all that much (if really only 30 hours)? Also the thing about the 100 hours/ 2 year super charger replace. I'm assuming this would mean I should look at a rebuilt super charger right off the back if I were to get something like this?

Can it happen, sure. But it is not the norm. And yes, unless they can PROVE it was rebuilt, you must assume it has not been. Their word means nothing. You want to see the receipt.

 

[Nosnibor]

the Craigslist link you posted was for an 08. the NADA link i gave was for the 215HP it just doesnt say it on that page. i would have the SC rebuilt.

lol I have no idea where I got 2009.

 

[Nosnibor]

Can it happen, sure. But it is not the norm. And yes, unless they can PROVE it was rebuilt, you must assume it has not been. Their word means nothing. You want to see the receipt.

I think what I meant to ask was even if it hasn't been 100 hours but over 2 years should I still look at having it done? With only 30 hours how bad could the SC be damaged? I guess I don't understand why the "2 year" mark is important.

 

[Coastiejoe]

I think what I meant to ask was even if it hasn't been 100 hours but over 2 years should I still look at having it done? With only 30 hours how bad could the SC be damaged? I guess I don't understand why the "2 year" mark is important.

Anything with ceramic washers needs changes instantly regardless of hours. When they fail, the ceramic parts drop to the oil bath, into the oil pump, and destroy the engine.

Once they are rebuilt with the UPDATED kits, which includes and updated shaft, Seadoo states they are good for 2 years. Most of us feel this is a selling ploy so that new owners are not so hesitant to buy a new ski with a SC'r.. That said, thousands have gone for 2 years and more, so Seadoo is pretty safe in stating the 2 year rebuild.

Salt water riding will lesson things as compared to fresh water. I am a recent mover to the salt water world and I can tell you that corrosion happens FAST. Like after three rides fast.

As far as waiting longer than 2 years, the issue is that other items become brittle and can fail. Such as bearing and the bearing cages. And much like is a ceramic washer fails, when you have a bearing failure or a cage comes apart, if follows the same path. To the oil bath, to the pump, to the engine...

 

[Nosnibor]

Anything with ceramic washers needs changes instantly regardless of hours. When they fail, the ceramic parts drop to the oil bath, into the oil pump, and destroy the engine.

Once they are rebuilt with the UPDATED kits, which includes and updated shaft, Seadoo states they are good for 2 years. Most of us feel this is a selling ploy so that new owners are not so hesitant to buy a new ski with a SC'r.. That said, thousands have gone for 2 years and more, so Seadoo is pretty safe in stating the 2 year rebuild.

Salt water riding will lesson things as compared to fresh water. I am a recent mover to the salt water world and I can tell you that corrosion happens FAST. Like after three rides fast.

As far as waiting longer than 2 years, the issue is that other items become brittle and can fail. Such as bearing and the bearing cages. And much like is a ceramic washer fails, when you have a bearing failure or a cage comes apart, if follows the same path. To the oil bath, to the pump, to the engine...

Thanks for the more in depth info. I'm just wondering if that 2 years is for a certain amount of use. Like what if it rains every weekend and I don't get out. Still needs to be replaced? Or should I be okay if I stick to every 100 hours? Sorry I am very new to all this.

 

[Nosnibor]

Also I will mainly be in a salt water area. I have heard about the corrosion before. As far as maintaining it...a rinse down when I get back and maybe flushing tap water through the motor? What is it with jetboats? Motor on then add water then water off and engine off?

 

[Coastiejoe]

Thanks for the more in depth info. I'm just wondering if that 2 years is for a certain amount of use. Like what if it rains every weekend and I don't get out. Still needs to be replaced? Or should I be okay if I stick to every 100 hours? Sorry I am very new to all this.

The every 100 hours is more than safe is you are capable of hitting it within the 1 yr or 2 yr rebuild period if it has been updated. Few people hit 100 hrs in a season. My 09 (bought it late 2010) has 55 hrs on it for example.

Granted, I lived in Ohio where riding was limited due to the waether, but even here in Florida I will not hit 100 hrs in a season let alone a few seasons..

 

[DLB]

Also I will mainly be in a salt water area. I have heard about the corrosion before. As far as maintaining it...a rinse down when I get back and maybe flushing tap water through the motor? What is it with jetboats? Motor on then add water then water off and engine off?

very important! do not have water on unless motor is running.

 

[Nosnibor]

The every 100 hours is more than safe is you are capable of hitting it within the 1 yr or 2 yr rebuild period if it has been updated. Few people hit 100 hrs in a season. My 09 (bought it late 2010) has 55 hrs on it for example.

Granted, I lived in Ohio where riding was limited due to the waether, but even here in Florida I will not hit 100 hrs in a season let alone a few seasons..

So the 100 is irrelevant. 2 years, hands down. Even if it was a fresh SC two years ago and never ran, rebuild it again.

 

[Coastiejoe]

Also I will mainly be in a salt water area. I have heard about the corrosion before. As far as maintaining it...a rinse down when I get back and maybe flushing tap water through the motor? What is it with jetboats? Motor on then add water then water off and engine off?

With the exception of the Mercury powered boats, it is ALWAYS, Motor on, water on, water off, motor off. And run time is to be like 45 seconds max. This is because you are not cooling the ceramic seal when using the hose. It is a FLUSH, as in you are flushing the engine. The water runs backwards when flushing as compared to the normal path/flow when riding the ski/boat.

Most use CRC and spray their engine down. I have just ordered a gallon for myself. If you don't protect the meatl, block, connections ect ect, they WILL corrode due to the salt.

 

[Coastiejoe]

I think what I meant to ask was even if it hasn't been 100 hours but over 2 years should I still look at having it done? With only 30 hours how bad could the SC be damaged? I guess I don't understand why the "2 year" mark is important.

Officially yes, but I can tell you many of the fresh water skis/boats that have five years on the SC'r with no rebuild. Salt vs Fresh is night and day. I will pull my SC'r near the end of the summer season as I am over the time, not the hours. Now that I am in salt water, it matters.