2007 Sea Ray 185 Sport Not Starting After Running

[The Fisch]

First time boat owner here, and not mechanically inclined, so patience appreciated. Trying to be as thorough as possible here because I'm not sure which details are pertinent and which aren't.

Bought a 2007 Sea Ray 185 Sport with a Mercruiser V-6 sterndrive 4.3L MPI Alpha/Bravo engine, back in June of 2020. Had about 140 hours on it, and had just had manifolds and gaskets replaced, as well as the battery and normal things like the impeller and oil. Ran great all of last summer. Winterized it, then took it out in late spring and was working fine again.

On about our third or fourth trip out this summer in 2021, I noticed the boat was so sluggish it wouldn't even get on plane with the throttle all the way down. It went from me being able to go over 40 mph, to only being able to go around 10 mph - 15 mph. Didn't matter the throttle or trim position, just wouldn't go any faster.

My mechanically savvy sister-in-law's husband helped me trouble shoot. Used Lucas Fuel Treatment and Sea Foam Motor Treatment in the fuel tank respectively, the spark plugs looked good, but it appeared that the distributor cap had some corrosion on the connections and the engine was only running on four of the six cylinders due to leaking sparks.

We replaced the ignition Sensor, the distributor cap rotor, the spark plug wires, and (since it was dinged up) put on a new Mercruiser propeller.

Took it out to the lake to test it and it ran well, despite not being *as* fast as before. Took it out one more time just me and my family and it ran efficiently.

Then on 7/30/21, we took my family of four out with my sister-in-law and our nephews and niece out (all young kids) and after running around on the lake for a couple of hours we stopped to pull in the tube, deflate it, and get all the kids in and dried off. Tried to start it back up, and wouldn't start. Tried multiple times then let the engine rest for about ten minutes with no luck, so had to get a tow back to the boat ramp.

Called around to various boat repair shops and the consensus was vapor lock, due to us being in central Texas, and the heat here. Everyone said they couldn't get to my boat for three plus weeks because of backlog, and I need it fixed ASAP. Took it out again, and it worked, though I was again noticing some sluggishness/not getting on plane or going as fast as I was accustomed.

Finally, took it out again last weekend and had some trouble getting it started initially, but it did start. Ran the boat for about twenty minutes getting to a quiet spot on the lake and stopped to swim and eat dinner. Kept the bilge blower on for the first ten minutes and opened the engine compartment to make sure we didn't have the vapor lock issue.

Tried starting it so we could pull our friends on a tube, and... no dice. Wouldn't start again. We tried for about fifteen minutes, then finally, by the grace of God, it very hesitantly started. Once it was started it was having the same issue as before I changed the ignition Sensor, distributor cap rotor, spark plug wires, and propeller: very sluggish, only getting up to about 10 mph - 15 mph. It did eventually get on plane, and I with the trim up I could get it to around 20 - 25 mph, but it was not reliable at all.

Haven't had it back out since. I bought a fuel filter so I could replace it, but outside of that I'm out of ideas. Fuel pump? Accelerator pump? Incorrect carburetor float?

Sincerely, any help or ideas you can give me would be greatly appreciated as I have all of my high school buddies coming to my house on Labor Day weekend to go out on the lake, and I have no idea if the boat will strand us in the middle of the lake...

 

[ColoSR]

My boat was doing the same thing, it was the fuel pump/cool fuel unit. My engine would run fine until it was under load, the mechanic figured it out by putting the boat on the dyno and testing the fuel pressure. It should be 40-42 psi, my old pump was only putting out 28-30. Replaced the cool fuel unit and it runs great.

that being said, I have had some trouble restarting on occasion when hot. I can advance the throttle and it starts every time so I am looking at the idle air control (IAC) valve as a potential problem.

not to offend, but do you know that you can push the button and advance the throttle to start the boat? I figured this out after my first tow due to vapor lock.

 

[GypsmJim]

You can continue to throw parts at it and hope for the best. Or, you can have a certified master Mercruiser mechanic diagnose and fix it.

Sorry, but boat ownership means that Summer is a bad time to get service. The only open times are usually BEFORE Memorial day.

Whatever you do, don't take that boat out again until you get it fixed. Nothing worse than being stranded. Forget Labor day. Its too late now. Your guests will just have to be disappointed.

 

[paulswagelock]

Sound like a failing fuel pump. Need to check fuel pressures.

 

[The Fisch]

Thank you @paulswagelock and @ColoSR! That was what is next on the checklist. It started right up with muffs on it in my driveway once I changed the fuel filter. Going to try and test it out in the water a bit, then most likely replace the fuel pump.

 

[Daniel1980]

I would have the carb cleaned with a new seal kit installed. My mechanic told me that ethanol fuel is hell on a carb. Swells stuff up real bad and boats have starting and stay running issues. A 2007 might desperately need this. Mine did and it solved 95% of my engine issues. Best thing I did to my boat after purchase. Carb cleaning!

 

[Arminius]

I gave my last boat to my brother. He seemed to keep throwing parts at it making small problems more confusing. In response to my urging to get a mechanic, he would hire guys who would admit they weren't comfortable with the old engine but he would keep them because he "liked them" and receive big bills while the boat declined. Jim's idea of getting a mechanic who is certified as competent sounds good. Balky contraptions can be analyzed or you can just throw parts at them. Analysis does require expertise or experience. Not to say you shouldn't take it out this weekend for an adventure. My old boat was quietly given to Goodwill.

 

[GypsmJim]

I would have the carb cleaned with a new seal kit installed. My mechanic told me that ethanol fuel is hell on a carb. Swells stuff up real bad and boats have starting and stay running issues. A 2007 might desperately need this. Mine did and it solved 95% of my engine issues. Best thing I did to my boat after purchase. Carb cleaning!

I know, I know, its what everybody says. Truth or urban legend?

I used to have to rebuild a carb every 7 or 8 years. Then, e10 came around. Pffftt. Haven't had to clean a carb in years.

My 1980 Ponch and my 1984 Stingray 3.0 liter have NEVER had the need to fix the carb. I don't know about swelling of parts, but I DO know that when I do the annual PMs with a touch of gumout the smoke comes out white and clean.

IMHO, the ethanol keeps the carb clean, it doesn't make it dirty. Heck, in the old days we used to add dry gas in the winter.....hahaha.

 

[Arminius]

The MPI is injected, no carb. I use pure gas, especially at the end of the season. Outboards I had during the ethanol transitional years were degraded. A '89 mercury 220 Magnum had clear fuel lines that turned yellow and became brittle, like glass. This early injected outboard ran about 60 psi to the injectors and a line failure could have caused a fire. Embrittlement of the plastics in the fuel system was addressed but I figure long term exposure, as to UV, will take its toll.