30HP Merc EFI Four Stroke Wiring

[pvanv]

If the bolt fits the washers and lever, odds are the hole is too big. Never had that problem.

 

[AGENT 37]

I noticed that the co-pilot washer, with the flat key protruding off the front, had a different size hole too so I took some measurements. The bolt is 8mm along with most of the hardware but the copilot washer an oval 10mm hole. I can't get a measurement on the swivel bracket bolt hole due to the tight quarters but am guessing it to be closer to a 10mm as the 8mm threads barely contact the hole threads going in and out of the hole. I'm contemplating getting a bolt that correctly fits the hole in the swivel bracket, grinding flats on the top half of it and doing some modification to the handle and washers to get them to fit over the larger bolt.

Of course now I'll probably have to disassemble the swivel bracket to also remove the stainless 8mm bolt that I sheared off for the friction bar. I didn't have a tap handy so I was working the bolt back and forth with some WD40 to get it slowly worked in and it sheared off flush with the upper steering bracket casting. There's almost enough clearance to drill it out from below... but not of course.

If there was a friction bolt to tighten on the steering shaft I would go that route but of course there isn't. Frustration finds me a lot lately.

 

[pvanv]

Is the nylock nut 8mm or 10mm? If 10mm, odds are that you have the wrong stud. Considering that the nut for the main starter switch was missing as well, perhaps someone had the kit out and was rooting through it, and some bits were accidentally left out or swapped from a different model kit. The co-pilot steering friction is far superior to the side friction bolt, and is instantly adjustable without a wrench. I have that setup on my 9.8 and love it.

 

[AGENT 37]

I agree, I've got the co-pilot friction on my 9.9 Merc and 15 Merc and love it. I just need to get the motor to hold course while I tend fishing lines and tightening up the side friction bolt has sufficed with the other motors I've run. For the meantime, I went ahead and rigged up some shock cord between the steering arm and the corners of the transom. It's getto but functional.

The nylock is 8mm as well as the two nylon washers, metal washer, and the handle. The copilot washer and the swivel bracket holes are the only larger drilled items. The bags of the kit were all sealed so I don't expect it was messed around with. I'll bring it up to the guy at the parts counter and see if he can reach out to Mercury for me to see what they have to say.

Yesterday's test run was kinda rough. The motor was dropping a cylinder occasionally and misfiring at various ranges of the power curve. Between last night and today I cleaned up the coil grounds, trimmed the spark plug wires and reinstalled the plug caps. The motor ran much better for today's water test no real noticeable power drops. It is still stalling out and hunting at idle though. I had a feeling that the very rusty idle speed control box looked suspect. By lightly tapping on it I was able to both correct and induce the stumbling and stalling. At one point, the motor was idling at probably about 1200 RPM for a good minute without slowing down. I tapped on the ISC and she instantly slowed down and stalled.

 

[AGENT 37]

I pulled the IAC valve off and checked it out. It looked nasty in the nipples but ohm checked fine. I cleaned it out with carb cleaner and actuated it with DC power on the bench several times and put it back on. The motor was running a bit better but still not perfect so I took it off for another cleaning and managed to have it fall out of my worn out hands in the process. One of the nipples sheared off and shot into oblivion. I'm having nothing but fun with this project! Guess we'll see what result the replacement part yields in a week or two.

 

[AGENT 37]

The replacement IAC valve got the motor running beautifully.

After communicating with Mercury tech services through our local dealership, it was determined that I somehow ended up with a swivel bracket drilled for a 3/8 - 24 threaded rod used on the 1C series serial number motors.

That was after breaking a bolt, an ez-out, a tungsten tap, and about 67 drill bits along with a tap that had to be cut down to custom length to clean out threads...Geesh.

Now I get to figure out if this motor just needs parts from the 1C serial number family with 3/8 -24 hardware, a blended family of parts from the OR serial number series and 1C serial number series, or some custom machining to get parts from the two series to work together.

What else can you do with a can of worms besides eat it one bite at a time?

 

[pvanv]

One trick that might work would be to drill/tap an 8mm ID bushing, and then thread the outside to 3/8, and sink that into the swivel bracket with lock-tite in the 3/8 threads.

 

[AGENT 37]

I'm laughing Paul.... That's essentially what I was trying to do when I snapped off an 8mm tap in the bushing/helicoil I had installed. It was a solid 4 hours of drilling. Fortunately, I only had to drill out about 1/3 of the thickness of the bracket to remove it and was able to save the upper 1/2 to 2/3 of the existing 3/8-24 threads. I never would have assumed that motor would use anything but a metric piece of hardware.

I do have an aluminum rod that I ran through a 3/8 -24 die to do exactly what you've suggested. If I go that route, I will make sure to drill and tap it BEFORE it goes into the swivel bracket. Working in the tight space on the underside of that thing is a significant challenge, especially around broken pieces of tap and drill bits.

 

[AGENT 37]

It is finished. I drilled out the helicoil, ran the tap, installed the bushing and she's good to go. I did my first run with the designed steering friction this past weekend and am happy to not be tending the tiller constantly while setting lines. It was an easy 32miles of running in 6-8' seas and 20kt winds.... wet.... but easy. I found no fish but I got caught in six rain squalls. It wasn't until half way through the run that I decided to bring out my beach umbrella, turn down wind, and take shelter from the weather. Much easier to do when the tiller stays put!

I'm now a happy owner of a re-badged MFS30B and the guy that just bought my old up-tuned NS25C2 was stoked on the deal he got. I sold it for the cost of parts that I put in to get it running and I think even his wife is happy since I was able to encourage him to get an ACR PLB by offering him a $50 discount on my asking price if he bought a PLB and brought me a copy of his NOAA registration.

Performance wise, I can top out my 1990 Avon Searider 4.0 meter at about 26kts WOT with this 30HP four stroke where as the old two stroke topped out at 32kts WOT. I'd never been able to do such a comparison between a two and four stroke of the same HP, from the same manufacturer, on the same boat. It really highlights what a lot of people have claimed about the two strokes out performing the four strokes. I'm not racing though, so I can embrace the lower top end for smoothness, low noise, no smoke, and fuel efficiency. The 13P Turning Point prop that I tried from the old two stroke made the rig a dog getting up on step with the four stroke so I sent it with the old two stroke and went with a 10P Solas/Tohatsu prop on this motor. It's giving me a better hole shot, hitting the same WOT ground speed, and staying under the RPM limiter with the boat loaded right. I might eventually try to get my hands on a 4-blade Mercury Spitfire prop but am content for now with what I'm running.

Thanks for your feedback working through this motor project with me Paul. I learned a lot and feel like I actually came out ahead on this one.

 

[pvanv]

My pleasure. Yes, the throttle response of a 2-stroke is quicker (less mass, and firing every downstroke), and in some cases, it will run faster on the same rig. As you noted, the smoothness, quietness, and fuel economy are often worth the change -- that and the fact that in the US (actually all of North America), you don't find many small 2-strokers any more.

If you do swap to a 4-blade prop, be vary careful to get the correct pitch. Since 4-bladers shovel more water, you will need to reduce pitch. Personally, I prefer to just barely bump into the rpm limiter when completely unloaded, so that in "real world" conditions, the boat comes right up to max wot rpm.