1995 Merc 200HP - its not broke. Should I fix it?

J

jvitiel

Junior Member
I bought a V two years ago with a 1995 Merc 200HP EFI on the back of it. I rebuilt the low pressure fuel pump and replaced the switch packs when I got it but since then it has run great - strong and smooth.

It can be hard to start once in a while but for a motor its age I feel its running very well. Still, the winter is here and in addition to the typical filters, hoses, impellers, tstats, seafoam etc. I don't mind doing some projects and/or preventive maintenance that will help keep it running its best.

So, I was thinking about removing the injectors and sending them out for cleaning and while I'm in there maybe changing the reeds out. I'm sure neither has been done in at least four seasons but I don't know anything beyond that.

So what say you? Do one? The other? Neither? Both? Again, it's pretty much running fine so I'm hesitant to fix something that isn't broken but if it saves me grief down the road then its a good idea.

Also, follow up question - if I take the injectors out, would I be able to inspect the reeds sufficiently without taking them out or do they really need to be checked from both sides (I'm guessing the latter but not sure)

Thanks as always !
 
Sending the injectors to brocato or somebody like that is a great idea. These are open loop systems meaning they don't really monitor the engine. They check coolant temp, throttle position, MAP, and RPM's, that's it. So if the injectors are not flowing properly, that's a good way to throw the whole system off and burn down a powerhead(most efi outboard failures are caused by bad injectors). Injector flow is critical to these systems. That said, they never started that great to begin with. I do know the TPS adjustment is CRITICAL to that engine, and if it's off more than .25 volts, it can really make it run like crap. I don't have a manual for one anymore, so I don't recall the idle TPS voltage setting off the top of my head anymore. I hada 95 XRI 150 EFI, and I do remember adjusting the TPS made a BIG difference. The other thing that helped mine was hooking up the choke function. I'd have to search to find it again, but theres a way to hook up the push to choke function of the ignition switch to the ecm so when you push the key in, the ECM will richen the mixture during the 1st 30 seconds of running. Even in the warm Florida waters it really helped cold starting by being able to richen the mixture manually when cold.
 
Thanks Ferm. I forgot to mention that I have a Brucato ECU. Amazingly it doesn't use the TPS at all - the wires are just dangling. Not sure if it could incorporate the choke but I would like that option. Maybe I'll send them an email.

Pretty sure I'm going to send them the injectors for cleaning. Should I do the reeds? I like the idea of plastic reeds but don't want to mess with them unnecessarily..
 
Doing the reeds shouldn't hurt, but avoid the boyesen 2 piece ones at all costs. I ran Tony Dukas Racing reeds, but Chris Carson I've heard makes some good ones too. The boyesons being a 2 piece design are just to thin, and WILL warp. I'm not much help on the brocato ecu, never messed with one. I do know they have an A+ reputation for all there work.
 
Brucato sells Carson reeds so I'll go that way and kill two birds with one stone. Thanks for your insight and happy Thanksgiving!
 
I put the Carson Reeds in my 200 Johnson looper a few years back and have had zero problems with them. Highly recommend them.
 
Update

So I took the motor apart today to send the injectors out for cleaning. Went easy. Again it seems to run fine but I was surprised by the amount of oil inside the throttle body (I pre-mix) and especially the gunk on the outside of the butterflys. I'v never been inside one of these before. Is that normal? See the pics at the attached link.

The reeds looked better than I though they would. Only two or three have a visible gap and it seemed like it was less than the .020 spec but I didn't measure them. I'm going to put new Carsons in anyway.

https://photos.app.goo.gl/807IZYfR9MMSNkIu2
 
I don't see anything abnormal. Those reeds still look really good IMO. The buildup of carbon is completely normal, and occurs on any throttle blade assembly that runs dry. Cleaning it is part of an induction service that shops reccomend be performed every 30K miles in a road going engine.
 
THEFERMANATOR said:
I don't see anything abnormal. Those reeds still look really good IMO. The buildup of carbon is completely normal, and occurs on any throttle blade assembly that runs dry. Cleaning it is part of an induction service that shops reccomend be performed every 30K miles in a road going engine.
Click to expand...

Thanks for the insight - much appreciated!
 
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