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1990 wellcraft 186 eclipse 4.3 L Mercruiser Alpha 1 Need help with steering?

S

spiderman

Member
Hello,
I have a 1990 wellcraft 186 eclipse 4.3 L Mercruiser Alpha 1.
Please,bare with me on explaining things.I took the boat out today.When I get the boat up to about 25 mph going straight.The steering starts to seem like I'm driving on snow or ice so to speak.Like if you have to slow down thinking something may happen.Hard to explain,like if the boat starts to pull one direction then the other.The feeling real does want you to slow down.I haven't had this boat for a long time.My first boat.A newby so to speak.I bought a new quicksilver 17 pitch prop for it a few weeks ago.Rpms are running a little high for the WOT.I'm looking to change it over to a 21-22 pitch to lower my rpms.But,I don't think the steering has to do with my prop.

Located on the sterndrive on the lower unit just above the propeller but,below the black sting ray plastic fin there is a round aluminum plate looks to have a small fin.I was told this is for adjusting if the boat pulls one way or the other when steering.The fin on the plate seems to look broke off or wore down.And the round plate is loose as turns clock or counter clock wise.It only turns a little bit like a 1/2 inch clock or counter clock.Is this part I'm trying to explan my problem?

How to remove this part to replace it is another.Looks like I have to remove the black plastic stingray fin to do so.
Is this round aluminum plate I'm talking about suppose to be tight or is it made to be loose.As move/turn a little?
 
spiderman said:
Hello,
I have a 1990 wellcraft 186 eclipse 4.3 L Mercruiser Alpha 1.
Please,bare with me on explaining things.I took the boat out today.When I get the boat up to about 25 mph going straight.The steering starts to seem like I'm driving on snow or ice so to speak.Like if you have to slow down thinking something may happen.Hard to explain,like if the boat starts to pull one direction then the other.The feeling real does want you to slow down.I haven't had this boat for a long time.My first boat.A newby so to speak.I bought a new quicksilver 17 pitch prop for it a few weeks ago.Rpms are running a little high for the WOT.I'm looking to change it over to a 21-22 pitch to lower my rpms.But,I don't think the steering has to do with my prop.

Located on the sterndrive on the lower unit just above the propeller but,below the black sting ray plastic fin there is a round aluminum plate looks to have a small fin.I was told this is for adjusting if the boat pulls one way or the other when steering.The fin on the plate seems to look broke off or wore down.And the round plate is loose as turns clock or counter clock wise.It only turns a little bit like a 1/2 inch clock or counter clock.Is this part I'm trying to explan my problem?

How to remove this part to replace it is another.Looks like I have to remove the black plastic stingray fin to do so.
Is this round aluminum plate I'm talking about suppose to be tight or is it made to be loose.As move/turn a little?
Click to expand...

Ayuh,.... It takes a 3/8" allen key, down through, from above...
 
The problem is the STINGRAY PLASTIC FIN!!

These devices are know to cause serious steering issues and Mercury Marine has sent out many bullitens saying they do not want them on there out drives.........

They are used for under powered boats to help them get on plain easier. The side effect is over steering issues........

Try removing it and see how the boat works (the way it was designed to)
 
Dan here In reply,STINGRAY PLASTIC FIN
(These devices are know to cause serious steering issues and Mercury Marine has sent out many bullitens saying they do not want them on there out drives).
Are you saying this STINGRAY PLASTIC FIN is a recall.And if I do remove this sting ray plastic fin.Do I put something on in replace of it or just simply take it off and be done?
Seems every sterndrive I seen on the lake has these sting ray fins install of them.From what your explaining this isn't a Mercruiser part.What was originally on it in replace of it nothing?

Back to this,round aluminum plate with a little fin part thing.This part that I'm trying to explain is located just above the prop.It 's about 4 inches round aluminum plate with a little fin .A friend told me one time it's for adjusting the steering if pulling going straight.I don't have major pulling problems.The boat does seem to have that side effect as over steering issues as feeling as if your on ice over 20-25 mph while going straight.This part (round aluminum plate)I'm trying to discribe is loose not tight.It turns clock or counter clock wize about a inch either direction.Is this normal?Is it suppose to turn "loose".It seems to be a very sloppy loose.The little fin on that part "round aluminum plate" is broke off.It's been broke since I got the boat.I was wondering why it was broke.Looks to me if someone may have broke it off to install a bigger dia propeller.Since the little fin is broke off I'm sure it won't work if adjusting anyway.I may be answering my own question here but,I need to buy that replacement part for starters I'm sure.
Just wonding if this part is ment to be loose as I discribed?

Last question,
That part I discribed (round aluminum plate with little fin)located just above the prop used for steering adjusting.
With one of the prop fins straight up.How much clearence/space should you have between the prop fin & that steering plate fin?I'm wonding if I have too big dia prop maybe giving me this problem as over steering.As of now I have about a 1/2 inch clearence.
When,I bought the boat it had a aluminum 19 pitch prop.I replaced it with a 17 pitch 1/2 inch bigger dia stainless quicksilver prop.Thinking if I have the room for it why not. If your prop is to big in dia.Will it cause over stearing?
Thanks!
Dan.
 
No I am not saying that the sting ray (brand) is the issue, The use of any type of fin on the outdrive is considered by the manufacturer to be wrong.

The original outdrive had NOTHING on it!!!!!!!!! Go to a boat dealer who sells mercruiser and look at NEW boats. NONE will have a fin on it... if one does it was done with out Mercruisers authorization............


I know what you were refering to, commonly called a TRIM TAB. It is a aid in steering, not a solve all steering issues. It serves a dual purpose, the other service is a sacrificial anode.

When adjusting it if the boat pulls to the left, turn it clockwise when looking down at it from the rear of the boat. If it pulls to the right then turn it counter clockwise when standing at the rear and looking down. Only adjust it about a 1/4 at a time. Typically it will only make the steering clean at a certain rpm range, (example) say 2000 - 3500 rpms. below and above it will most likely still pull some.

One other side effect is if you think about it, the "fin" forces the bow down, this aids the boat to plain off faster BUT, it also keeps forcing the bow down, if you are not trimming your outdrive up after you plain off then it will feel like you are going to "dive down" all the time. Even when trimming the outdrive up it still has a weird feeling with the "fin". The bottom line is, it is most likely the "fin" Dont care what others have or use on there boats.

If they drive them into a rock pile will you also?

The "fin" or whale tail or any number of other names used to describe it is a 100% known cause of steering issues.

Agian, remove it and then adjust the trim tab if needed.

By the way you most likely lost approximatly 3-5 mph at top speed with the fin..........

The prop typically does NOT cause steering problems. Is your SKEG all there? the part of the outdrive below the prop. it is shaped like a V. if it has been damaged and broken off this acts like a rudder. if it is broken or partial missing then the boat will also have steering issues.

Take a picture of the outdribve from the side of the boat and post it so we can see..........
 
Last edited:
Agian, remove it and then adjust the trim tab if needed.
Click to expand...

Ayuh,... Ditto that,... take the whaletail off....

The torque tabs come in several off-sets, if prop interference is encountered....
Or if it ain't much, Grind the tab for 'bout 1/4" clearance from the prop...

If ya got P/S,... ya can use the flat plate anode...

But ditch the whaletail.....
 
i have trim tabs on mine the cheap ones works good,on my baja to get on plane! theses guys told me to take the whale tale off i did now works good with the trim tabs no steering probs!
 
bondo said:
Ayuh,... Ditto that,... take the whaletail off....

The torque tabs come in several off-sets, if prop interference is encountered....
Or if it ain't much, Grind the tab for 'bout 1/4" clearance from the prop...<(That's strange you said that cause someone already grinded it just as you said.)

If ya got P/S,... ya can use the flat plate anode...

But ditch the whaletail.....
Click to expand...
<What do use in place of it nothing?
 
kghost said:
No I am not saying that the sting ray (brand) is the issue, The use of any type of fin on the outdrive is considered by the manufacturer to be wrong.

The original outdrive had NOTHING on it!!!!!!!!! Go to a boat dealer who sells mercruiser and look at NEW boats. NONE will have a fin on it... if one does it was done with out Mercruisers authorization............


I know what you were refering to, commonly called a TRIM TAB. It is a aid in steering, not a solve all steering issues. It serves a dual purpose, the other service is a sacrificial anode.

When adjusting it if the boat pulls to the left, turn it clockwise when looking down at it from the rear of the boat. If it pulls to the right then turn it counter clockwise when standing at the rear and looking down. Only adjust it about a 1/4 at a time. Typically it will only make the steering clean at a certain rpm range, (example) say 2000 - 3500 rpms. below and above it will most likely still pull some.

One other side effect is if you think about it, the "fin" forces the bow down, this aids the boat to plain off faster BUT, it also keeps forcing the bow down, if you are not trimming your outdrive up after you plain off then it will feel like you are going to "dive down" all the time. Even when trimming the outdrive up it still has a weird feeling with the "fin". The bottom line is, it is most likely the "fin" Dont care what others have or use on there boats.

If they drive them into a rock pile will you also?

The "fin" or whale tail or any number of other names used to describe it is a 100% known cause of steering issues.

Agian, remove it and then adjust the trim tab if needed.

By the way you most likely lost approximatly 3-5 mph at top speed with the fin..........

The prop typically does NOT cause steering problems. Is your SKEG all there? the part of the outdrive below the prop. it is shaped like a V. if it has been damaged and broken off this acts like a rudder. if it is broken or partial missing then the boat will also have steering issues.

Take a picture of the outdribve from the side of the boat and post it so we can see..........
Click to expand...

I see the V that your talking about Yes I have the V looks fine no damage.As for using the sting ray fin I have on the boat.I also,understand what you are saying as forces the bow down.I feel that when boat high speed.As for that trim Tab.It was real loose & sloppy.I used a allin wrench today and tighten it up straight allined with the drive.I will do what you say about removing the stingray fin and run without it.I live up north La Porte,Indiana I normally boat in Local Pine Lake.To me it seem's every Mercruiser sterndrive boat on the lake has these sting ray fins.I just don't understand how this is a problem.My friend has a 18 ft.4 cyclinder Mercruiser searay with the same sting ray fin.He states no problems.Maybe the style or the engine size matters I don't know.As for photos,There really not needed.It's your basic Mercruiser alpha 1 sterndrive is all.It is the trim tab as you stated I'm talking about.
The main problem I'm having is when going straight about 20 mph seems to feel like I loose stearing and boat seems to lean to the right hand side.It's strange to discribe.sure makes you wanna slow done for sure.I guess the words for it is "over stearing"unless there is another word for it.It sure scaries the crap out of ya.I do feel the noise of the boat should be lower then what it is when going fast.I always run the trim down all the way all the time.Never mess with the trim up & down button.If I raise the trim up a little brings the noise up.I don't wanna flip the boat.Lol.I'm not in the need for speed, 20-30 mph top for me.I do want to feel safe tho.Removing the stingray fin,will it cause my noise to go up higher at 20-30 mph?
Thanks!
 
I bought this 1990 wellcraft 186 eclipse 4.3 L Mercruiser Alpha 1 off of ebay boat angles last yr during the winter.
Was told that the only thing wrong with it was the exhaust manifold was cracked as needed welded or replaced.So,when spring came I decided to start looking over the boat more.And found that the floor & supports was all roughted out.Foam in the floor was full soaked with water.I redid the floor and supports.6 weeks later I took it on the water.Found I was leaking water into the hull.Found that the exhaust manifolds was fine no damage.I found that the bellows was leaking.And throwing gear oil into the boat fromthe drive shaft area.I replaced all upper & lower unit seals,bellows.Gimble bearing was in nice shape.So,now the boat stays dry.runs sweat.other then that over stearing problem if that's what it is.
 
The reason poeple use the "fin" on an outdrive is as I explained, NOT ENOUGH POWER.

Many boats are sold at a lower price with a smaller powered engines in them to save on $$$, if you put a 4 cylinder motor in a 18 or 19 ft boat it is sold at a more affordable price, now put 4 grown adults and you have a slug of a boat.

Now put a V6 in the same boat and it will be much better and most likely operate as expected. (time to plain and towing power and top speed).

There are many here who post who have 20 - 22 ft boats with 4 cylinders in them........they need more than a "fin" to help them out.

Also it is how one intends to use the boat, if you only want something to get from point A to point B then a underpowered boat will work. If you want towing power, power enough to handle you and your friends/family and supplies then you need the appropriate power fer length of boat.
 
Well,my boat is a 18 1/2 ft.with a 4.3 V6 Mercruiser alpha 1.I don't understand why this fin was placed on this boat in the first place as before I bought it.I see what your saying about a boat with no power.As 4 cylinders and such.It seems I have all the power I need to do any job.As for tubing or hauling 6 people in the boat.It has the power & the pull.The problem is the boat wants to lean to one side then the steering seems loose after about 20-25 mph.Scaires the crap out of ya.I'll take it out Saturday with the fin off and try it ,see what happens after that.I guess they call it over steering.
 
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