1150 Link & Sync Question

[jakec]

Ok just did my water trial. I started by warming up the engine. Then I went to bump into gear (tied to dock). I had to raise the idle and then readjust the throttle cable to get it to bump into gear and maintain without dying.

Then I untied from the dock and putted around with my dad steering while I adjusted the idle screws. I was starting from 2 turns out (2 turns per the Merc Son videos on youtube).

(His instructions are to start with all 2 turns out, then turn in to stumble, then out 1/2 from there. after that turn all 3 carbs out an additional 1/4. Then if no hole shot turn all 3 carbs out additional 1/2)

I adjusted the first two carbs and found that the sweet spot was about 1.5 turns out. However once I started turning in the final carb it died and had a hard time running and wouldn't go into gear without dying, so I set them all back to 2 turns. I figured I they liked to be at 2 turns and left it there for now.

Then I tried some accelerating just to test the linkage and make sure the engine wasn't gona die, and then finally tried the hole shot. It definitely has a hole shot, my dad said he almost fell down when I hit the throttle haha. I can definitely lift the boat up on plane real quick.

My only concern is that the outboard is throwing a lot of water up. I have a video attached. I'm changing the RPM as I film to see how it reacts.

Video

Also, here is a pic of my idle screw. I'm just wondering if this is normal for it to be screwed in this far.

 

[jimmbo]

Spray like that could mean the Engine is trimmed in too far, and/or is too low on the transom. I suspect a bit of both. What hole is the trim/tilt rod in, counting the one closest to the transom as #1?

I love the Snarl the Inline 6 makes. Did you have a Tach working? If so what RPMs at WOT?

Idle speed is speced at 600 - 650 in gear

As for the Idle Stop Screw... Pictures in my books show it looking much the same

I never liked adjusting the Idle mixture on multiple Carbs. When I was a teenager we had Evinrude and Johnson V4s, there were 4 carbs to fiddle with. I always found if they were rich, the engine didn't Idle as Smooth, but there was no bog on Acceleration. My 84 Merc 115 was a real Problem Child. It was constantly bogging, no matter how rich the Idle was set. The Merc Service Rep eventually set the Pickup Timing way out of Spec and it was okay after that. After 14 yrs I traded it off, and I often wondered if anyone ever reset it to Spec, having the Bog return.

 

[jakec]

Yeah this had NO bog at all, it didn't really like idling but when I slammed the throttle down it just took off. My last boat had an evinrude 55 and it was like you described.

I didn't get the tach hooked up yet. But I was able to rev higher than is shown in the video, I just immediately backed it down so it isn't shown.

Here's a pic of the outboard mounted. the transom is just a little over 20" total height (started with 20" tall core and added fiberglass, fairing, paint). The corner between the transom and the hull is about 110* maybe? And there is a slight radius of about 1" due to my craftmanship However it is consistent at least. I think I am about 1" from cavitation plate to the bottom of the keel, but I'm not sure if the radius is affecting the cavitation or even these stabilization fins. I have the pin set to the second hole, since the transom has the negative angle.

My power trim is working so I can try that next time. I don't think there's an easy way to raise the outboard without drilling new holes in the transom, right? if so I think it'll have to stay where it is haha.

 

[jakec]

Also the guy I've been watching on youtube, Merc Son, he has a video where he does the link & sync and the idle is crazy high so he runs over and turns the idle spark advance down to 0*. So I guess people are going out of spec if they know what they're doing..

 

[jimmbo]

Okay, I think I see the Spray problem, Those wings bolted to the Antiventilation Plate. If the Engine is a little Low, the Water will come above the AV Plate, hit the Wing things and... I think the engine is a little low, but the Picture is taken from too high up. A pic level(camera not aimed up or down) taken at the Height of the Boat bottom, from the side. Another thing you could do, is run a Straight Edge under the bottom of the Hull, and sticking out by the motor, and see where the top of the Straight Edge is in relation to the Bottom of the AV Plate.
I didn't know you had Power Trim on it.

As for going out of Spec, If a Company Service Rep changes the Pickup timing, I don't have an Issue, as a Company Rep did it and if the engine were die a Horrible Twitching Death, it would be on Him. When it comes to others fiddling with things, throwing the Specs out the Window, some guys so know their Stuff, others, well some can't figure out their Butt from a Hole in the Ground. As you have found out, the Linkages on these engines are a bit of VooDoo, and making a Change, on one thing can result in an Unwanted Change elsewhere

 

[jakec]

I'll get a pic tomorrow. If the engine is too low, what should I do? I already decided if this engine ever comes off I'm getting a 4 stroke! haha.

When I throw the wheel around on plane the boat kinda drifts like a car instead of leaning in to the turn, do you think that's due to the barrel back shape? Or is that the stabilizer fins? It resists leaning and really makes you feel like you're gona get thrown out of the boat.

 

[jimmbo]

Unless you want to start filling and drilling holes, not much? I guess an Jackplate could be used to raise the Engine and provide some setback as well. But lets see what the Straight Edge reveals. Boats with shallower Vees tend to be a bit Skittish on turns.
Those Fins... Myself I would remove them, take them to the Deepest part of the Lake, attach some weight to them and throw them as far as possible

 

[jakec]

Ha! Ok I will take it off. I'm not one for stability anyways. And yeah I would need to fill my holes, sand, fair and paint, then drill new holes. No thanks. Maybe next winter. This hull does have an extremely shallow V at the stern.

 

[Chris1956]

The hull looks pretty flat bottomed. She will slide quite easily with a flat bottom.

I would remove the whale tail. They are useful for getting on plane, but you say that is not an issue, and they usually scrub off some top speed.

BTW that motor has 1976-77 decals on it.

 

[jimmbo]

The First Post said it was a 77.

 

[jakec]

I did like how quick it got on plane. I wonder how much it's helping.

 

[jimmbo]

The motor looks a little low, but it is also trimmed in at the moment.
The Rounded edge of where the Transom meets the bottom concerns me. That too will send water upwards, and steal a few MPH from the top speed.
Getting rid of the wing thing should reduce a lot of that Water Fountain back there.
Horrible Devices, a Solution in search of a Problem, is what they are. If they were of any Value, the Engine manufacturers would have made the AV Plate in that Shape

 

[jakec]

Yeah I think I am about 1/4" low. And I wish it didn't have the radius, but I think I would've needed to build it up with filler basically. The outside of the transom had to be built from scratch so when I was wrapping 4 layers of 1700 fabric around that corner, the radius was unavoidable. I didn't know what the consequences would be though.

So, should I leave the pin on the second hole, and try trimming up on plane?

 

[jimmbo]

I'm not sure what the Geometry is all about
You can place the Pin in the hole closest to the Transom, or even throw it away.
I added an Arrow tp the pic pointing to the AV Plate

 

[jakec]

Sorry my sketch there was trying to show 1-1/2" spacing between the hull and cavitation plate, which I've read is standard. Where is the hull meant to be relative to the lower plate you're pointing to?

Also I guess I don't understand how trim works yet, would I want to create MORE negative angle on the outboard? Removing the pin like you said?

Also this is way off topic but I used lead airgun BBs to block the crossovers on the carbs since they are the perfect shape, a barb with a flare. I was just wondering if you think the lead will dissolve or something?

 

[jimmbo]

Here is a bit of info from Mercury regarding engine height



Power Trim: Trim in/down fully to get on Plane, raising the engine as boat gets on plane. As speed increases, trim out until boat starts to Porpuss<sp>, then trim in a bit till it stops, or until the Engine trims out as high as the Limit Switch allows. That is important on your engine as the you can tilt the engine up, out past the Support Guides(Transom Brackets) where there is not Lateral support for the engine. There is a Limit switch to prevent the Trim Button from raising the motor higher than that, and a separate Button(Trailer) is used to bring it up higher
Lead has been used by Carburetor manufacturers to plug passages on carbs

 

[jakec]

Oh I see. I was looking at the wrong fin. So I am what, an inch low? If you draw a straight line (level) from transom to outboard it is less than what's shown on the ruler since the keel is angled down steeply. Well jeez why would that happen? Transom is just too short? I thought if I built a 20" transom for a 20" motor it would just work!

As for the trim limit switch I have currently bypassed it because it wasn't working (didn't allow it to raise at all until it was bypassed). So I will get a phone GPS app and use the porpoising as a stopping point. I've never experienced that before but I have read about it so it will be interesting to see what it feels like.

Is there anything really bad about running the engine too low, or is it just decreased performance?

 

[jakec]

My boat is heavy and I plan to load it down with 4 people and camping gear at minimum. so maybe the low application wont be that bad, per the diagram. as long as I can still get on plane.

 

[jimmbo]

Extra Drag, and can create excessive spray.
Phone app? What for?
Porpoising is annoying as Hell.

Remember basic Trigonometry? You are dealing with a Triangle. A Outboard Boat Transom, is never 90 degrees to the Hull Bottom, at least it's not supposed to be, most, but not all, are between 7 and 12 Degrees off Vertical. So in reality, if a motor has a 20 inch shaft, the Transom really needs to be a bit taller. If a transom is 20 inches, then the motor needs to be a bit less than 20 inches. That is one of the reasons they started making Transom Brackets that allow changes to Engine Height, but Mercury didn't start doing that until the mid 80s. OMC Started in 1967 on their V4s, but they had an Oddball Drop-in Bracket, that they used until 73

 

[jakec]

Oh I see. the planar surface of the transom is 20" but the vertical distance is less due to the angle. Wow, I should have thought of that.

The phone GPS app for speed, would help me determine best trim position at ideal rpm correct? I assume trimming up would make the speed increase to a peak point, and then speed would begin to decline as it goes too high? Or do you maintain speed and just start hopping along? ha