my 787 "hydrolocked"?

[admin8]

One engine in my 1997 Challenger 1800 wouldn't start this year. It turns over for 5 or 10 seconds and stalls. If I unscrew the spark plugs it will spin over freely but oil sprays out of one of the cylinders. I've read that this is a bad seal on the crankshaft and requires a replacement of the crank.
Questions: Why can't the seal just be replaced? If I replace the crank, do I have to rebuild the entire lower end (connecting rod bearings, main bearings etc)? What is the typical cost for the parts for a project like this? Is this something a backyard mechanic can tackle or would I be sorry I tried to do it myself?
thanks!

 

[seadoosnipe]

Rotary...

One engine in my 1997 Challenger 1800 wouldn't start this year. It turns over for 5 or 10 seconds and stalls. If I unscrew the spark plugs it will spin over freely but oil sprays out of one of the cylinders. I've read that this is a bad seal on the crankshaft and requires a replacement of the crank.
Questions: Why can't the seal just be replaced? If I replace the crank, do I have to rebuild the entire lower end (connecting rod bearings, main bearings etc)? What is the typical cost for the parts for a project like this? Is this something a backyard mechanic can tackle or would I be sorry I tried to do it myself?
thanks!

Lots of times, this is caused by the rotary seal. If you note on your oil tank, you have a second line on the bottom, one to the rotary, the other to your injection (thats the one with the filter on it). At the top, you have the vent line.

The seals on this chamber, around the crank, are put on while the crank is in two pieces. There is no way for you to seperate the crank and replace these seals. I dont' event think they sell them.

If your ski sat for a while, you might get the seal to reset. Blow out all that oil, as much as you can, then put a dab of fuel (no oil) into the cylinders. Pop the plugs back in and try to get a start. If you can get the motor to run, then you might heat the seal and get it to reset. This is only if the motor has been sitting for any period of time...........:cheers:

 

[admin8]

Reset the seal?

Thanks snipe, that is certainly easy enough to be worth a try. The boat had sat for several years prior to my buying it a year ago but it ran fine all last summer. Of course being in the northeast it sat over the winter, from end of August until beginning of July (short season here!). So the seal might not be worn out, just not seating correctly?

 

[Carlosm]

Carlosm

Hello guys Im pretty new to this site, and I think is a really cool way to get intimate with your seadoo. I need some help on resolving an issue I have with my 1996 Seadoo challenger with a single engine 787. When I throtle up on it the rpms climb pretty high to about 7000. but the boat only stays at 15mph. it sound like its just not switching into gear or something. I would appreciate any help possible to resolve this issue. it's weird but it doesn't happen all the time, but it's becoming more requent. thx guys!

 

[phough5757]

seals

Mine was the same way when I bought it.
With a good battery and good starter, Pull the plugs and crank the motor.
Put a rag or something over the plug holes or it will paint the ceiling with oil.
I started by using a hand operated vacuum pump hose stuffed down the carbs.
Sucked as much oil out that I could then started cranking the motor.
Fresh set of plugs and a little chocking and it smoked out the neighborhood.
It has been good ever since. I use hose pinchers on the oil lines over the winter. Long winters here also.

 

[admin8]

Vacuum out the oil?

Thanks Phough, wish I had tried that earlier in the season, I just assumed that it was toast and I put it back away in the barn. Maybe we will still get another nice weekend.
Hey, is that your wife?

 

[admin8]

boat not going over 15mph?

Carlos, have you checked very carefully for debris or weeds on the impeller or on the grate? takes very little to disrupt the thrust of the water jet.
If there is no debris, you probably need a new wear ring- the housing that the impeller spins in. Stay away from the shallow water!

 

[Carlosm]

Carlos, have you checked very carefully for debris or weeds on the impeller or on the grate? takes very little to disrupt the thrust of the water jet.
If there is no debris, you probably need a new wear ring- the housing that the impeller spins in. Stay away from the shallow water!

Yes I checked it all. I already had it serviced because I didn't get parts fast enough for labor day weekend, so $300 dollars later I'm ok.
I have another issue now, it seems that my carbs are acting up, when I thortle up my boat wants to turn off unless I pull on the choke a little bit, then it starts to take off. I really want to get familiar with my boat and hopefully fix the issue my self....Any sugestions will be greatly appreciate it..
thx guys!!!!!!

 

[admin8]

reply- engine hesitates upon acceleration

What you describe sounds very much lilke the "accelerator pump" needing to be refurbed. Its a fancy name but actually a simple device- kind of like a squirt gun. Whenever you push the throttle forward it simply squirts gas into the throat. Buy a carb rebuild kit and the parts will be there. Don't rebuild the entire carb or even remove it- just remove the accel pump.

 

[dsw222]

What you describe sounds very much lilke the "accelerator pump" needing to be refurbed. Its a fancy name but actually a simple device- kind of like a squirt gun. Whenever you push the throttle forward it simply squirts gas into the throat. Buy a carb rebuild kit and the parts will be there. Don't rebuild the entire carb or even remove it- just remove the accel pump.

I believe that the accelerator pump diaphragms are not included in the mikuni OEM kits. I had to buy mine separate. (I used parker yamaha)