I have been searching and searching for some help on the Seadoo Forums and can't seem to get any help so I am hoping you guys might be able to help.
Boat is a 01 Seadoo Utopia 185 with the 200hp Mercury Optimax M2 Jet Drive. I bought it from my boss for $500 cdn it's worth north of 10k here. It was one of 6 boats that he owned, it was NEVER used just sat at the dock and was winterized/de-winterized every year by a marina and prior to me buying the boat it had sat in storage for 2 years at a marina. When I bought it they de-winterized and water tested it.
I used it one day, ran great but it was doing something funny while going at a steady speed the engine's tone would change, like it would bog down for a bit then back to normal then bog a little then back to normal. You could hear it and also feel it lose speed/power a little but it still seemed to work good, was getting 50mph which is it's top speed.
Second time about a week later I got out, run it for 5 minutes and it dies instantly, It cranks but won't start. I take it out of the water and bring it to a Seadoo/Mercury dealership they find it was just a fuel pump fuse but also notice that Cyl 5 has low compression, won't read above 100psi. Their suggestion is to buy a new block from Mercury which runs about $5500 + all the labour to rebuild it....does this seem right?
I find this a bit odd since it was running good the last time so I take it out on the lake yesterday and sure enough, after idling/going slow for a bit I take it up to half throttle, it ran good then I heard that same noise but this time, it didn't go back to normal. As well, I couldn't go more then 30mph so I brought it back to the cottage for fear of doing more damage
**Disclaimer** I am a car guy, I've rebuilt car engines, did engine swaps, electronics/EFI upgrades etc. very handy with cars but never worked on a boat, this is my first boat and the wife only let me have it because it was so cheap for what it was worth, we thought we were getting a crazy deal not knowing of course we would have this problem. My boss never used the boat, it was parked for 2 years so it's not like he was trying to pull a fast one on me. Now my wife is ok with me fixing it if I can get it done as cheap as possible**End Disclaimer**
So, here are my questions and options that I see:
1-Could they have done the compression test incorrectly? Is there a how-to somewhere to help with doing this? Even if it's just another Merc motor not this one specifically?
2-Is there anything I can do while the engine is still in the boat in hopes that it's something other then the engine? Could it be spark plugs/wires? I keep hearing about "clipping" plug wires when doing a plug change?
3-Is there something else that would cause low compression? Something I should look for?
4-Can I rip it apart in the boat and replace the piston rings like you would do on a car? Or does the engine need to come out completely and taken in to be rebuilt?
5-I keep reading about "Powerhead" is this a complete assembly that I can take out and get that rebuilt without having to pull the whole engine?
Just looking for advice from others who seem to have a lot more knowledge on fixing/rebuilding Mercury engines rather then paying a marina to put in a brand new engine.
Couple things to know if you're pulling the powerhead out. You willl need a lifting ring that screws into the top of the flywheel, the only safe way to lift the powerhead off the jet unit. Beyond that, it is a matter of the throttle cable, electrical harness, and exhaust hoses and a water line, oil line, and fuel line, and battery cables.
Investigate getting a Mercury remanufactured powerhead availble at a Mercury dealership. I suggest if you are not familiar with the product, an authorized dealer is best to undress and redress the replacement powerhead.
Break the replacement powerhead in - the engine can be set by the dealer to supply double oil during the break in cycle. Don't baby it too much, I did some testing for Mercury in a previous life and found I needed 2500 RPM in a SeaDoo to get the double oil feature to function. Three hours at least at reduced throttle settings before getting on it hard.
Hope this information helps!
Thanks for the info, I did see that lifting ring you were talking about. This might be a stupid question but if I buy the service manual or service manual CD from eBay will it go through the removal of the power head from the boat?
I have a hard time wrapping my head around how these Merc's work, is there info on that? I'm used to car engines.
Merc P/N is 90-881986. The one I have is January 2001, I would think it has been udated since.
There are 11 M10x1.5 nuts securing the powerhead to the pump. Plug the oil line or tie it up so the oil from the tank doesn't siphon in to the bilge.
Ok, I went up to the cottage this weekend and started on the boat Saturday morning. I checked compression on all 6 Cylinders, they were all between 120-125psi. I immediately noticed something wrong when I saw the black engine paint on the plugs...meaning they were original from when the engine was built, and they looked BAD.
I called the shop where I had the boat 2 weeks ago and told him that I checked myself and it had equal compression on all 6 cylinders, he suggested it was because it now had oil in that cyl and it was sealing everything up...LOL I then asked him about the plugs and all he said was "naw, we didn't think of changing them" Lesson learned, I am never going to that place again.
Ok, so in the small town where the cottage is I was able to get 6 new plugs, they were NOT cheap. I put in 6 new plugs with some Dielectric grease, ensured everything was put back properly. Then when I was about to put the engine cover back on I noticed the crank sensor was unplugged...it was REALLY hard to get that plug to clip but I did.
I started the boat, idled for a while, then went 10mph for about 10 minutes, seemed to run great so I opened here up, no hesitation at all, nice engine sound, it was windy but was able to get to 45mph on the gauge. I was happy but skeptical that this was the only thing it needed.
Later in the day I went out again in the boat and performed great again.
This morning the wife and I went for a nice 1 hour ride around the lake, cruising at 30mph the engine purred like a kitty. Opened her up, it was calmer today on the water and it actually went over 50mph with no hesitation at all.
So, for the price of 6 plugs, it looks like it's fixed.....I'll keep my fingers crossed. Either way, the engine isn't toast like the shop said it was. If I wasn't mechanically inclined I would of had them replace the engine....