Just bought first boat, died the second day out. Fueling issue? 240 merc in a utopia

[R00st]

I recently moved to a river town and decided to sell my motorcycle to buy my family a boat. After lengthy research I decided I wanted a jet boat and narrowed it down to a sea Doo. I was looking far and wide and finally found what I thought was a good buy: a 2002 utopia 185 with the merc 240. The boat has a wake tower/speakers, a recently replaced power head (40 hours) and 1 hour on a fully replaced jet drive (with receipts for the jet drive which they used their insurance to fix, to the tune of $3k). The boat spent some summers on a lift so the gel coat is cracked in a few places and the interior is not as nice as a couple boats I saw. I want reliability not show ability so I drove 5 hours one way to buy it. Asking was $9k and I paid $8200.

I noticed the battery was slightly slow to crank during the test run so I replaced the 27 size Napa battery in there with a 29 size for more capacity and cranking amps. The first time I used the boat was last Saturday and I burned half a tank and she ran very well except for the very end of the day (hour 3 of usage) when at part throttle. She hesitated and then regained power. I thought it was maybe just a fluke but 5 minutes later it did it again at 90% throttle, and almost killed the motor. After a second or two I revved it up again to 50% throttle and it again nesitated. I was getting very worried so brought it back to shore and loaded it up. I texted the seller asking how old the fuel was and he said "about a year old but I used stabil". This made me think maybe I had some water in the tank or the fuel was bad. I topped the tank off with fresh shell 93 (17 gallons worth) hoping the 93 would balance out the what was probably 84 octane in the tank from sitting so long. I also want to note it smokes considerably upon startup but no smoke once warmed up.

I launched the boat with fingers crossed that the fresh fuel would do it. I let her idle for about 3 minutes, then went to about 15% throttle for 3 minutes to get some heat in the block before I got on it. I increased from 15% throttle to maybe 30% and she fell HARD on her face and shut off. I restarted and couldn't give her more than 10% throttle or she would die. While idling back to dock I hit the bilge pump switch (which I've run the previous day without issue) and it killed the motor.

So....where do i start? I feel like I have a clogged injector, bad pump, fouled plugs or possibly water in the fuel. I also just read the article about the temp head sensors going bad and thought maybe that should be on the list too.

What's the easiest place to start from the above list? Anything else I should be considering based on the symptoms? Id rather not take it to a marina until I've troubleshot the basics so I dont have to fork over $120/hour for them to do the same.

Any help is appreciated!!!

 

[Coastiejoe]

The two things you should do first are a compression test and a Fuel Pressure test.

Both are critical to the Merc Engine...

 

[R00st]

Where and how do I check fuel pressure on this engine? What should pressure be?

What about compression range on cylinders?

 

[Coastiejoe]

[MENTION=16022]Dr Honda[/MENTION] knows these engines well. He can likely provide good input.

You will need to splice into the line to check the FP Pressure if yours doesn't have a Shrader Valve. At idle it is over 100 PSI for example on DI skis, (which you don't have, just making a point).

 

[stepdrill]

I feel your pain. I just bought 02 speedster first day out it died. 2 voltage regulators and a stator to the tune of $1250 it's running great now. Good luck :cheers:

 

[R00st]

Thanks coaster. Step, I read your thread, that's a bit pricey but luckily you got her going!

 

[UKGlenn]

Have you checked the charge on the battery? I know its new but i had a similar problem last year caused by a faulty alternator and broken belt. Are you getting any alarms/beeping? Is the oil light coming on in the fuel gauge?

 

[Dr Honda]

Welcome... and sorry to hear about your issue. But... lets figure it out.


To start... We need to know what engine you have. I know you said it's the 240 EFI... but when it was replaced... they may have put in the new style engine. The fastest way to know is for you to just post a pic or two of the engine.

But... assuming it's an early 240...

The port side temp sender is kind of a "Tune-up" item. When it goes bad... you burn extra fuel, and it's hard to start. But open throttle isn't affected. So... it's probably not the issue.

Also... year old fuel... if treated, isn't a big deal. But if you think there was junk in the fuel... you have 2 filters that can be changed. There is a small metal fitting on the bottom of the lift pump... that's a filter. (Replace it) Then you have a big spin on filter. Change it too.

As Coastie said... fuel pressure and compression is a great place to start. I don't think you will find a compression issue... but it's good to have a base line with a new-to-you 2-stroke toy.

Fuel pressure on your boat is pretty easy. You have a Schrader valve on top of the regulator. Hook a gauge on it... and have someone watch it. You are looking for 36 psi. You need to check fuel pressure with a load... so you have to put it in the water, and give it a run.



OK.... a question for you. When it starts to stumble/stall... is it "Soft" like it's sputtering, or slowly looses power?? Or does it die quick, like someone is turning the key?

 

[R00st]

UKGlenn: I did for a moment consider that its possibly a charging issue- as I thought it was very odd that the tiny load the bilge pump would draw on the system would kill the boat. I think ill start with this. If the battery isnt holding a charge I will check to see if the alternator is producing a charge and if not I will replace it and probably throw a new belt in as well. I have only spent about an hour working on this boat and have ZERO marine mechanical experience but have limited car/atv/motorcycle experience, so hopefully that transfers easily. Is the alternator an easy job? Without looking at the engine bay I cant even picture where the alternator is at.

Would low voltage prevent the engine from revving? I am assuming yes since the high pressure pumps probably require a decent amperage to fire and low amperage= no fuel. That would make sense as to how the boat slowly started to have issues- a slight hiccup- then got worse and worse as the voltage decreased.

Dr. Honda- I will take a picture of the engine when I get home today. I will disregard the temp sender for now and add it to a laundry list of maintenance items I plan to replace. I will also plan to order new filters just for the fact I have no idea how old they are and its cheap insurance. I will also check the compression so I have a baseline and can monitor it over time.

The very first time it stumbled I was cruising at maybe 35 mph and it was a VERY quick and soft hesitation that was just a quick pause and then power resumed. The ones toward the end were much more harsh- and one of them when cruising at maybe 20mph almost felt like we hit something, the power was cut so quickly. There is no sputtering- its X rpm or it kills the boat (for the last 4-5 episodes). On the way back to the boat launch I had it at 5% throttle and that is all she would take, or she would just shut off.

Here is to hoping for a charging issue *fingers crossed* !

I need to buy a compression gauge and a gauge to check the fuel pressure, as well as find a source for mercury parts online (fuel filters x2 and the water separator- is that one of the two fuel filters or a whole separate filter?) - any suggestions? If there are other cheap insurance parts I should be replacing, add them to the list. I want a reliable boat! I also have amazon prime so if any of the above are on there I can get the parts/tools quickly.

Thanks everyone for the warm welcome and the assistance- it is rare these days to find a forum where people genuinely want to help you. I am a member of probably 50+ forums over the years and have stopped going to most of them because its too much drama.

 

[A4effort]

Most parts I get are online eBay/Amazon. Some can be bought at local discount marine supply. We have marine trading post here in SWFL. You should locate a discount store in your area. They are very handy when you want the boat fixed asap. Maybe I missed it but did you get your boat fixed? If yes what was the outcome?