225 opti issues
 

One of my buddies has a pair of 225 opti's and he's claiming that the port one doesn't jump quite like the stb. I haven't been on the boat before so I'm guessing he's having issues getting RPM out of the engine. I told him to check his fuel filters since he didn't know when the last time they were changed was. I'm not too familiar with merc's.....especially the optimax motors. Does anyone have some pointers on what to look for. I'm supposed to seatrial the boat on friday with him and see if I can resolve the issue.

Fuel filters is the first place to go. There's a cartridge filter inside the cowling many people overlook, and it's built into the high-pressure tank just before the HP pump. Next place to look is compression. If just one cylinder is low, that's a 17% loss of power on that engine.

The Optimax design is essentially a roots-type supercharged 2-stroke motor, using a belt-driven air compressor to force air into the cylinders along with a HPDI fuel injection system.

I appreciate the info. I'll bring the compression guage for kicks but I have a feeling that his issue is from lack of maintenance. Thanks again. I'll let you know what I find.

These new motors are really hard to figure, other than the basics like filters, good luck

If you have a noticeable miss on the optis it is easy to isolate the cylinder that is the culprit. Unplug each fuel injector one at a time while its idling until there is no noticeable difference, usually an air injector ends up being the culprit.

Alright.....so I changed the primary and secondary fuel filters and found enough sand and crap to re-do Jupiter's beach. Unfortunately, it didn't solve the issue when we ran it. The engine doesn't sound like it's missing either, it simply has no balls. The boat will jump up on plane but the stb engine is dragging the port up to R.P.M. At full throttle, the port engine is turning around 4500 and the stb is turning a tick over 5k. Would I hear a noticable miss with the engine in the water? My evinrude seemed to do the same thing when a coil quit but it never sounded like it was missing in the water. Could it be the air pump itself?? I will try unplugging one injector at a time and see what I come up with. I'm also going to put a fresh set of plugs in it. Do they need to be indexed like they do on a ficht?

No they Don't have to be indexed. Was the compression good.

The plugs are around $25.00/ea. Platinum, and do not require indexing like the E-tec. I could see a coil being the culprit. Test spark and compression.
By eliminating spark and compression, you can systematically move to fuel delivery/air injection.

good call - isolate and eliminate, one at a time

The compression was good in all cylinders. They all stayed at or around 120 psi so that's nothing to frown at. I'm going to isolate the coils next and then fuel system if the ignition doesn't solve it. Thanks again. I'll keep ya'll posted on what I find.

Aaron

Check the air pressure out of the compressor, too. The compressor is actually a funtional supercharger, and reduced pressure means reduced power.

The spark plugs can be purchased at auto zone for about 7.00 a piece. There is a honda v6 car that uses the same plug.

:o Sounds like a deal on the plugs. Some people bought them from a Merc Dealer at $25/copy. Ask me how I know? LOL.

Are the part #'s the same? What Application?

Alright....so I went to the boat the other day to do some more hunting. There is a noticable miss on the port engine when compared to the stb. The stb. engine has that sound like every piston is trying to get ahead of the next one and the port sits there and idles smooth with a noticable thump. I isolated it to the bottom left cylinder (when you're facing the back of the engine). I pulled the plug, which looked really sooted up, and used the owners compression tester to show him that compression wasn't the issue. He refuses to believe that his issue is from a lack of maintenance. Think the guage would read worth a sh**? Heck no. Headed back tonight with my guage which I know works. UGH, what a headache chasing good tools around!! Anyways, I tested the coils for spark and all of them are firing so at least they are eliminated. The guy doesn't know when plugs were last changed, and if they're anything like the fuel filters, it's been awhile. I'll post back soon and let ya'll know what I find. Multiple trips are a pain in the butt. I'm going to laugh if it just ends up being a faulty plug.

Aaron

I got it. I checked coils, compression, changed plugs, checked for bad wires and checked air pressure and fuel pressure....everything checked out. I started the engine and ran it up to 1100 r.p.m. or so then started unplugging injectors one at a time. I isolated it to the two top injectors. The top right one will click like it wants to work but it doesn't change the way the engine runs. When I unplug the top left one, nothing happens at all. No clicking, no nothing. All the other injectors actually shut the engine down when unplugged. My next question is where to find new injectors and how much are they usually. This may sound like a dumb question, but before you laugh, I work on diesels for a living. All of our injectors are usually remaufactured or servicable. Obviously if there's a less expensive route, that's the way I'd like to go. Thanks again for all the help guys. It's much appreciated.

Aaron

About 300. A piece for air injectors thru mercury I would try eBay, that was what I suspected the one that clicks may recover after sonic cleaning .there is a resistance test you can do I will try tomorrow to look up the resistance range and post it.

You might try one of the folks that does the sonic cleaning and flowing of injectors, maybe they have a cheaper solution.

Tony Brucato for injector cleaning or solutions

Thank you for the help gentlemen!! I got her all fixed up and tickin like a timex again. We were able to take it out during mini season and it never missed a beat. I ended up finding an air injector and a fuel injector at a local shop out of an engine that blew up with fairly low hours on it. I think he said that it caught on fire actually. I was able to pick both of them up for 200 bucks........not too bad; and it was a pretty straight forward job once I figured it out. Again, I appreciate all the help. This is a good bunch on here!!

Aaron

Good job capt.