1998 Sportster 1800 Problems

[Bobbuff]

Well yesterday was the first day that I have actually been able to see what all the hype is about when it comes to my seadoo. When I first put it in the water it was AWESOME. However after about thirty minutes of running I started having the same problem that I was before with my starboard motor.

It will literally get up to about 6k rpms and then cuts out. Sometimes it will shut completely off and sometimes it wont. It seems to be fine at 4k but any higher and it cuts out. I just recently rebuilt the carb and replaced the gas lines. It seemed to have worked but only for a limited amount of time.

The guy I took it to told me originally that there was a whole in the diaphragm but that has now been replaced so I am at a loss. What I am thinking is that a bolt or something has backed out and I am now sucking air somewhere but I am not sure.

Also, when this problem seems to be happening, I am getting a lot of excess vibrations out of the motor that aren't normally there. Any thought???????

 

[m.colley]

Out of curiosity, did you have both carbs rebuilt, port & starboard, or did you have just starboard carb worked on when it was acting up?? Sounds like port carb needs to be cleaned/rebuilt. Just my .02 worth

 

[Bobbuff]

I just rebuilt the starboard side. That is the side that is still giving me this problem. The port side motor is running great

 

[jhjesse]

I just rebuilt the starboard side. That is the side that is still giving me this problem. The port side motor is running great

When you replaced the fuel lines did you clean out the fuel filter/water separator?? Many times when re attaching the bowl the 0 ring does not get seated properly causing air to be introduced into the fuel system causing a fuel delivery problem.

Does your boat have external fuel pumps? Have you taken them apart and cleaned/tested them?

Usually if you are sucking air from a loose screw/leaking gasket etc., the engine will run away with itself.

 

[Bobbuff]

It has the external pump and I have not checked or tested those at all. I also replaced the fuel filter/ water separator.

When I first put it in yesterday I had thought that whatever the problem was I has solved it by rebuilding the carb. Before, It would start out doing this and yesterday it actually gave me so good running time even though it was limited.

 

[howie099]

Here is the easy test for the fuel pump. Swap them between the engines and give that a try. Usually when you open them up you mess the pumps up since you can't buy the parts. Also the pumps use to have a gray tempo line for the pulse line you should replace that since they will gum up and kill the pump. They don't sell the pumps anymore so you need to retro fit a mikuni dual one and plug one of the lines. They are like $35 if you need one. Jhjeese is right those O-rings suck on the water/fuel separators and get over sized over time and get pinched and cut. I would also install some Fram G2 fuel filters inline right before the pumps. If you are getting any junk from the tank you could just be clogging the fuel filters again. It is usually the carb ones that get clogged.

I would swap the pumps and give it a try first after oking all the fuel lines.

 

[noswal_j]

If it runs fine at 4k then cuts out if you go above....could be voltage regulator rectifier...just a thought

 

[Dr Honda]

If it runs fine at 4k then cuts out if you go above....could be voltage regulator rectifier...just a thought

It could be... but the power gets into the entire system... so it would be likely that both engines would start to cut.


So the question is... do you have 2 batteries, and have the charging separated? if you do... then try removing the red wires on the regulators... and see if it clears up.


BUT... I'm thinking you have a fuel issue. Either the pump can't keep up, or you still have a carb issue.

 

[Bobbuff]

No I do not have two batteries. I am also thinking that my problem is within the fuel system. What I cant wrap my head around is how the problem wasnt there when I put in for the first time after the carb . Then returned a short period of time after running perfect. Before I rebuilt the carb the problem always was there from the time I left the dock. After I was able to cruise around at a steady 6500 rpms for quite a while before it started doing it again.

 

[howie099]

You still could of sucked up junk in the carb again from the tank or scale in the lines. Think about it if the fuel pump is all gummed up you could be passing that on right back to the clean carb those pumps came with the tempo lines for the pulse so you would have that green slim buidling up not as fast as the regular fuel lines but it would happen. I would spend the $35 on the fuel pump or swap pumps to see if the problem happens on the other eingine just don't runt the engine with the bad pump the boat will go with 1 engine. For $35 that is not a large investment it would cost you way more than that to drag it to a dealer.

 

[Bobbuff]

When you say the "tempo lines" are those the gray lines that everyone is talking about. There are two still remaing on my boat that I have not replaced yet, do you think that might be the problem. Also, when I am out of the water it will start and idle fine. Its not until I get it in the water that I get the problems. You are right that will definetly be cheaper that taking it to a dealer. I took it to a mechanic the first time it was happening and he stated the reason why was because there was a hole in the diaphragm. He also told me he did a compression check and it was at 120psi on each cylinder and that it was normal. He stated "Hell even the new boats dont have 140 to 150 psi" because thats what I stated it should be at. Needless to say I dont really believe he ever did a compression check.

 

[Guest_User]

When you say the "tempo lines" are those the gray lines that everyone is talking about. There are two still remaing on my boat that I have not replaced yet, do you think that might be the problem. Also, when I am out of the water it will start and idle fine. Its not until I get it in the water that I get the problems. You are right that will definetly be cheaper that taking it to a dealer. I took it to a mechanic the first time it was happening and he stated the reason why was because there was a hole in the diaphragm. He also told me he did a compression check and it was at 120psi on each cylinder and that it was normal. He stated "Hell even the new boats dont have 140 to 150 psi" because thats what I stated it should be at. Needless to say I dont really believe he ever did a compression check.

there is NO LOAD on the engines in the driveway...
and fire that mechanic...

you could easily test the compression yourself with a known good gauge...

 

[Bobbuff]

I did, LOL. and yes I am just trying to find where to buy one at. Also, if I had a compression problems then my boat wouldnt have ran as well as it did for the short period of time. I must say this is my first Seadoo or jet boat and I dont remember a time that I was more excited over the performance of a boat when it was working well.

 

[Dr Honda]

............. I took it to a mechanic the first time it was happening and he stated the reason why was because there was a hole in the diaphragm. He also told me he did a compression check and it was at 120psi on each cylinder and that it was normal. He stated "Hell even the new boats dont have 140 to 150 psi" because thats what I stated it should be at. Needless to say I dont really believe he ever did a compression check.

Ummmmmm......


And this is why mechanics get a bad name. That guys was obviously retarded, and can't function in the real world.

A seadoo engine... 800 and smaller... 150 psi is a perfect engine. 120 generally won't run in the water.

So... go to harbor fright, and buy the $19 tool... and check it yourself.

And... since we may be chasing low compression... do that before we go any deeper.

 

[howie099]

Yes remove the tempo lines. They should be coming from the engine to the fule pump AKA pulse lines. I bet they are green on the inside. You can use 1/4 automotive fule line or Tygon hose. The mechanic would only know there is a hole in the diaphram if he tested or looked at it. I bet he just guessed. Every engine manufacture has different specs for the compression. I worked on a 4 stoke scotter that needed to have min 145 PSI to even start and little 150cc scooter. Your engines should be in the 140's for a compression check. You can rent or buy a tool. Just get one with a check valve in it.