Bass Boat - Trim - Planing Problems

[MAtkins]

I think I'm dealing with part lack of experience and part (the most part) faulty equipment.
I've got a Bass Nautique w/ a Merc. Black Max 150 XR2 on it.

When I first take off, I've got trim all the way down. The stern digs in and the bow shoots up.
The motor does not rev up.
As I move I pull the trim up to level the boat out. It doesn't work.
The motor just bogs and keeps pushing the bow up into the air.
It won't take off.

I've gotten it to do it twice and when it did the boat skimmed across the water @ around 50 mph. with no problem at all.

When I idle, the engine doesn't like it. It will idle but it'll cut off real easy.
When I put it into gear it's a fight to get it to move the boat before it just stalls.
If I can get it to go it seems OK.

I've had suggestions that the carbs need cleaned or completely rebuilt.
The spark plugs were recently replaced. I *think* the fuel filter was also.
What do I need to do to get it to run better?

I suspect the limits for trim up & trim down are wrong.
Here are some pics of my trim:

All the way up (without using the button to trim for trailering):
Is this high enough?


Almost all the way down. the motor lower is on the ground now.
It could trim lower in the water. It seems to tuck under the boat a bit.
Is this too low?

 

[glenn property of pam]

Re: Bass Boat - Trim - Planing Problems

keep it trimmed all the way down until you are on plane and the boat feels nose heavy. If the nose is still high then dont trim up. once the boat is settled start to trim up until the steering gets loose. thats a small ammount of trim before the nose starts to bounce.
theres no advantage to trimming all the way up. some boats only trim between down and 1/4 up others need way more trim up and thats alot to do with the angle of the transom.

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

Thanks. I'll try that next.
Right now I've got a bit of rewiring to do.
Apparently I've got a loose wire on the trim down control.

 

[glenn property of pam]

Re: Bass Boat - Trim - Planing Problems

every boat is diffrent so pratice will show you what your boat likes. I have in the past put black tape over the trim gauge when friends have driven the boat as its better to drive by the feel of the boat and just think of the trim switch as a connection to the front of the boat. If you want the front down trim down if you want the front up trim up. Most bass boats ive been on have a dead zone between 7mph and 20mph so its always better to go wot trimmed all the way back to get past that zone then throttle back and trim the boat out.
A good running engine trimmed down (prop will loose some bite) will except full throttle and run like a scolded dog. If you engine bogs out then you need to service the engine. If it takes wot but seems to take a while to get to full power then check the pitch of the prop

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

Thanks.
That helps a lot and it is exactly what I have not been doing.
I've been trimming up to get the nose down.

I might get a chance to try again this evening.

 

[Chris1956]

Re: Bass Boat - Trim - Planing Problems

You might remove that whale-tail. I doubt you need it and it can cause handling issues. What pitch prop do you have?

Tuck the motor under the transom for starting and trim up until boat handles easily. Different speeds require different trim amounts.

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

I took it out again. It really hates to idle. When I put it into gear it'd rather stall than go.
I've pretty much gotta max the throttle to get it to engage and go.

Once I'm running it moves real slow. I played with the trim. It seemed to respond a bit better with the trim not quite fully down.
If I can get it right, the boat will *slowly* gain speed. If I can get it to keep accelerating it'll eventually flatten out and take off.
Once it's up to speed it's fine. It runs real well and it's fast.
I plane up to the limit and that definitely helps. The boat pulls up out of the water just a bit and I gain a little more speed.

If I slow down too much it loses the momentum and I've gotta start all over again.
It's real hard to get it up to speed.

I'm thinking I've got motor problems but I'm not sure where to start to rectify it.

 

[glenn property of pam]

Re: Bass Boat - Trim - Planing Problems

start by looking at the prop and getting the pitch number so we have a idea what you are playing with. you may have to remove the nut to see the number.

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

OK, thanks. I've tried to find it before and I can see engraved letters/numbers but I don't really know what I'm looking for.
I see, engraved on the prop:
QUICKSILVER 48 13982 A5 21P

I'm guessing the pitch is 21.
Should I be seeing something else or does that tell the pitch?

 

[glenn property of pam]

Re: Bass Boat - Trim - Planing Problems

21 pitch is high but the motor should be able to spin that up with no lag so its time to service the motor. As this motor is new to you the full works would be the best idea
compression-spark test-carb clean-water pump-new plugs-change water seperator-link and sync. I dont think you are going to find any major problems but it will give you a good base line on the motors health and a good carb clean and ignition check should correct the problem with the idle issue and the laggy throttle up.
The worst part on a outboard is one cylinder can miss fire,drop,run lean and its hard to notice except for loss of power but all off the problems can lead to damadge to that cylinder so its best to test then correct any problem early or service and prevent the problem before they begin

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

OK, thanks. Looks like I've got some work to do.

I just ordered a compression tester. I've got an old one but I don't trust it.
It looks like it'd be hard to accomplish without a service manual.
OK, I hope 'Seloc' is alright. I bought a used one.

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

I finally got a compression tester and tested the compression.
I don't know the number sequence of the cylinders.
I've got a Seloc manual on the motor but I don't see it in there.

I suspected bad news and that's what I got.
Here's what I found.
Looking from behind prop.
TOP
105 - 80
89 - 97
105 - 90

So, what now?

 

[blindreef]

Re: Bass Boat - Trim - Planing Problems

I am no expert on engine compression, but those results don't look all that alarming to me?! I wonder what the expected compression is on this motor.

 

[CharlieB]

Re: Bass Boat - Trim - Planing Problems

Original compression with a good gauge was 120 to 125

Before condemning the motor I would do a de-carb to see if that brings those numbers up.

I would also squirt those carbs with a good carb cleaner solvent. Wally World Super Tech carb cleaner is about the cheapest and best solvent I have found.

The de-carb solution may assist in clearing anything in the carb jets.

Search 'de-carb' for details

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

OK, decarb is complete and it didn't help.
In fact, the 2 cylinders with 105 compression dropped to 100.

The motor still likes to stall a lot. I have to baby it to get it into gear and moving before it stalls.
It seems to run better when I first start it.
Once it's been running for a bit it's more inclined to stall.

I took it onto the lake to blow the carbon out of it and had a lot of trouble getting up to plane.
I really had to baby it. I thought it acted like I was flooding it a bit.
Once I did it was fine. The whale tail was definitely up out of the water. I don't see what it's doing for me.

When I was running Seafoam through it I had the cover off the carb throats.
I noticed gas was coming out of the carb throats.

So now my question is, is the compression the reason the motor isn't running right?
I need to make a decision: should I just rebuild the motor or start troubleshooting the fuel system?

 

[CharlieB]

Re: Bass Boat - Trim - Planing Problems

Lower compression makes less power.

With the front off the air box, trim the motor level, NOT running, squeeze the primer and hold it like a firm handshake while looking down the carb throats. You can push the control arm WOT so you can see past the butterflys.

Is ANY fuel coming out of the carbs? If yes, order carb kits, the needles are leaking and need replacement, flooding will cause it to die and make it hard to start.

Repeat the de-carb, then run the motor to clean out all the stuff loosened by the de-carb. Retest compression again.

Fingers crossed.

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

Thanks CharlieB for your help.
I'll try that tomorrow.
It dawned on me that I never checked the cylinders for spark.
So, I'll do that first.

I'm gonna take that Whale Tail off too and see if that helps me get up to plane easier.

I suspect the carbs.
Is there a carb kit for an '84 Black Max XR2 that includes needles & seats?
Where's the best place to get that?

I'll redo the de-carb and post my findings here.

 

[daveswaves]

Re: Bass Boat - Trim - Planing Problems

Charlie B has you on the right track with the carbs, there is one other thing that puzzles me. You said the whale tail is out of the water at speed. It sounds like you have a stern lifting prop. That in combination with a whale tail is going to be poor performing. As Charlie suggested (and you promised) take the whale tail off. That 21P is a little steep, especially for an engine that is not running correctly.
See if you can borrow a 17P prop to do your troubleshooting with. When you are happy with the way the engine is running, then you can experiment with props. Hope this helps.

 

[Dukedog]

Re: Bass Boat - Trim - Planing Problems

Try ta find ya a OEM manual for it. Ya got more problems than just a "trim" issue. Comp numbers are low but that could be just tha guage. When your just idling trim tha motor at least level or a tad positive. If it does better it could be carbs or just idle timing that's not to good. There is no reason a little 2.0 150 with tha 2 ta I gears (less its been changed) won't turn that prop when its All right......

 

[MAtkins]

Re: Bass Boat - Trim - Planing Problems

I checked for spark today. All 6 cylinders are getting good spark from what I can see.
I don't have a spark plug tester but in high sunlight I can see sparks jump to ground for each one.

The carbs are a puzzle. The top carb, starboard jet seems to leak intermittently.
The other ones seem OK.
I just ran the motor with the silencer off and watched the carbs as it ran.
The top carb's starboard jet is definitely pouring gas out of it as I run the motor.
The gas is running down the faces of the carb throats from there.
Where is the best place $$ to get a carb rebuild kit including needles & seats?

I don't know where I might find a smaller prop.
The whale tail is coming off before I take it out again.
We'll see what that does.

I looked for an OEM manual and never found one.
I've got a Seloc manual for it.