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1995 Yamaha RA1100T
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Discussion Starter · #1 ·
I want to start by saying I'm very new to actually owning jet skis up until now I've only ever rented. I decided that I was going to buy something very inexpensive for my kids and I for our first experience which was probably my first mistake.
I purchased my 1995 Wave raider 1100 from a guy on marketplace who said that it ran great and had great compression. I showed up with money in hand and he showed me by putting gas in the intake that it fired right up however the gas tank was empty, he had gotten rid of the 2-stroke oil pump saying they all go bad. And all I need to do was take it to the lake premix gas and go.
Took it to the lake put in the premix gas it did nothing, it would fire if you put gasoline in the intake but would not stay running. I called the guy back to see what he knew, and I got the as far as he knew everything was fine just clean the carbs routine.
So I did some homework looking at forums took apart the carbs cleaned everything up and noticed that the diaphragms were kind of brittle but still intact so I put it back together and fired it up and it ran a little bit. So I took it to the lake. And if you played with the choke and played with the throttle eventually it would go and in fact had a top speed the first time of 52.3 mph based on GPS speedometer. (Of course the multifunction display on it is inop)
Took it home and decided what I needed to do was a top end gasket kit so I did that, took it out the next day and got it to go 55 mph but it would still bog down and you still couldn't really get to do anything without playing with the choke.
Decided at that point to invest in a carb kit so I got the three carb kit and put a new diaphragms put in the float needle but did not go into the inner workings of the car because I was afraid of stripping out the Philips head screws.
Took it back out and again had some of the same problems but this time had a speed recorded of 56.5 miles per hour and then one run at 57 mph which I thought was amazing.
A guy was there saw me having trouble and asked if I'd check the compression. I said no so I pulled out my compression tool and it said that I was only getting 70 to 80 in each of the three carbs. And he said that was my problem. But my questions are:
1. If I only had 70 to 80 psi in pistons, how was I going 55 and 57 mph?
2. I put silicone on top of the existing weather stripping to try and keep water out of the hole and when I did it seemed like my boat was starving for air could that be part of the problem?
3. I did mess with the needles for the idle screws but then put them back to factory would that be part of the problem?
4. Could this all be just the carbs needing the inner workings cleared out?
5. When I have the jet ski on land with a hose it runs and fires and seems perfect.why?
6. I took pictures of my pistons and the walls and there is no scoring or any signs of extreme Wear could I get away with putting standard rings in to build compression back?

I know I've given a lot of information to ask a lot of questions I appreciate any and all feedback.
 

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1995 Yamaha RA1100T
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7 Posts
Discussion Starter · #2 ·
I want to start by saying I'm very new to actually owning jet skis up until now I've only ever rented. I decided that I was going to buy something very inexpensive for my kids and I for our first experience which was probably my first mistake.
I purchased my 1995 Wave raider 1100 from a guy on marketplace who said that it ran great and had great compression. I showed up with money in hand and he showed me by putting gas in the intake that it fired right up however the gas tank was empty, he had gotten rid of the 2-stroke oil pump saying they all go bad. And all I need to do was take it to the lake premix gas and go.
Took it to the lake put in the premix gas it did nothing, it would fire if you put gasoline in the intake but would not stay running. I called the guy back to see what he knew, and I got the as far as he knew everything was fine just clean the carbs routine.
So I did some homework looking at forums took apart the carbs cleaned everything up and noticed that the diaphragms were kind of brittle but still intact so I put it back together and fired it up and it ran a little bit. So I took it to the lake. And if you played with the choke and played with the throttle eventually it would go and in fact had a top speed the first time of 52.3 mph based on GPS speedometer. (Of course the multifunction display on it is inop)
Took it home and decided what I needed to do was a top end gasket kit so I did that, took it out the next day and got it to go 55 mph but it would still bog down and you still couldn't really get to do anything without playing with the choke.
Decided at that point to invest in a carb kit so I got the three carb kit and put a new diaphragms put in the float needle but did not go into the inner workings of the car because I was afraid of stripping out the Philips head screws.
Took it back out and again had some of the same problems but this time had a speed recorded of 56.5 miles per hour and then one run at 57 mph which I thought was amazing.
A guy was there saw me having trouble and asked if I'd check the compression. I said no so I pulled out my compression tool and it said that I was only getting 70 to 80 in each of the three carbs. And he said that was my problem. But my questions are:
1. If I only had 70 to 80 psi in pistons, how was I going 55 and 57 mph?
2. I put silicone on top of the existing weather stripping to try and keep water out of the hole and when I did it seemed like my boat was starving for air could that be part of the problem?
3. I did mess with the needles for the idle screws but then put them back to factory would that be part of the problem?
4. Could this all be just the carbs needing the inner workings cleared out?
5. When I have the jet ski on land with a hose it runs and fires and seems perfect.why?
6. I took pictures of my pistons and the walls and there is no scoring or any signs of extreme Wear could I get away with putting standard rings in to build compression back?

I know I've given a lot of information to ask a lot of questions I appreciate any and all feedback.
Quick update I just had a friend bring over a new compression gauge and it turns out buying ones at harbor freight is a waste of money I have $110 110 and 100 as my PSI so I don't think my problem is compression...
 

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1995 Yamaha RA1100T
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Discussion Starter · #3 ·
Quick update I just had a friend bring over a new compression gauge and it turns out buying ones at harbor freight is a waste of money I have $110 110 and 100 as my PSI so I don't think my problem is compression...
I decided to start tearing it down to see if the read valve was bad and the pictures will show you what I found and I kept going deeper and deeper and I'm just curious if anybody thinks it's a salvageable project?
It looks as though a previous owner had some type of issue where they welded the bottom of the crankcase, and that of course this is what I'm dealing with with the current cylinder but I don't understand why I still had 95psi?
Also whoever at last use RTV to join the case together is that supposed to be a gasket? For what I have in it what I think I'm going to do is just order a piston put everything back together with fresh gaskets tighten everything down to torque specs and see what happens
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Looks like that engine was thrown together by the last owner. Base gasket
looked horrible.

You need to pressure test the crankcase before you complete the engine.
Good possibility that there is a lot of porosity in the welds. The case may
not be flat too.

Detonation destroys, it cracks pistons, destroys ring lands and seizes
pistons. Preignition melts. But no melting. Detonation on the rear cylinder
is often caused by a heavy load on the engine that twists the crank and
advances the ignition timing.

The pistons were probably really cheap poor quality pistons too.

You need to inspect the crank too and inspect the impeller too (pitch
and brand).

Lots of work ahead. But a warning, if the cause is not found, it will
happen again.


Bill M.
 

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1995 Yamaha RA1100T
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Discussion Starter · #5 ·
Looks like that engine was thrown together by the last owner. Base gasket
looked horrible.

You need to pressure test the crankcase before you complete the engine.
Good possibility that there is a lot of porosity in the welds. The case may
not be flat too.

Detonation destroys, it cracks pistons, destroys ring lands and seizes
pistons. Preignition melts. But no melting. Detonation on the rear cylinder
is often caused by a heavy load on the engine that twists the crank and
advances the ignition timing.

The pistons were probably really cheap poor quality pistons too.

You need to inspect the crank too and inspect the impeller too (pitch
and brand).

Lots of work ahead. But a warning, if the cause is not found, it will
happen again.


Bill M.
Thank you for the response. I paid $1500 for the wave raider and the trailer... I guess I ended up with a $1500 trailer... I don't see the point in throwing good money after bad.
You are absolutely correct, if problem is not found it will repeat itself.
 

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Many Yamaha triples continue to run well on only 2 cylinders, and
so their owners continue riding them until they melt down completely.

Either that or they are not going to let a little power loss ruin their
weekend. Many watercraft engines are seized repeatedly 5 to 10
times or more and don't stop riding until the engine finally refuses
to restart.


Bill M.
 
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