What am I missing, Help required

[bucyrusboater]

Here is my story. Purchased a 1985 Bayliner, Volvo Penta I/O AQ125B, Sterndrive 270. First boat, kids wanted a light to med project boat. Well we got it all right.

Here is the final problem, then I will list what I have done and checked.

Problem: While running FOT I only get 2700rpm's and GPS speed = 16, with trim tabs down, can almost get boat to plane. When in reverse, outboard pops up, like it want to come out of water. I get no speed in reverse.

Here is what I have done:
New prop = 15x15L (This matched what was already on boat)
Tune Up, timing is set to 6degr at TDC, while at idle of 800rpm
Compression: 1=184,2=158,3=184,4=184 (Within the specs of 70%)
Temp gauge reads = 180, no signs of it to be wrong
New tachometer
Oil Change
Rebulit Carb
Starts up great, sounds great even at FOT. Manual says cruise RPM = 4500, so I know I am missing some power. When not in gear, RPM's cruise up higher than FOT.

I could really use some advise on what to check next.

I know know what boat stands for: "bout another thousand"

Thanks in advance,
John

 

[bucyrusboater]

Re: What am I missing, Help required

Compression is good.

I used a timing light, and checked to make sure timing advances while trottling up, and it does.

What is the best way to check the fuel pump?

 

[Don S]

Re: What am I missing, Help required

You are WAY off in WOT (Wide Open Throttle) rpm have a look at the list below. Especially do the tests in #3

http://forums.iboats.com/showthread.php?t=295070

When in reverse, outboard pops up, like it want to come out of water.

The lockdown mechanism is either worn or broken or way out of adjustment.
Here is a link to the OEM drive manual. Should help you figure out what is wrong with it.
http://www.4shared.com/account/file...rive_service_manual.html?sId=fqPPXCI4tOnfkdm0

Here is the link to your engine manual also.
http://www.4shared.com/account/file...5_AB_Service_Manual.html?sId=fqPPXCI4tOnfkdm0

 

[bucyrusboater]

Re: What am I missing, Help required

OK, Going to following the fuel system checks, and will let everyone know the results and status. Thanks for the advise< should have this all checked today.

 

[bucyrusboater]

Re: What am I missing, Help required

Thanks for the manuals, only had an electronic version, this will be helpful.

1?) Do I need to remove the stern drive to adjust the lockdown mechanism or can this be done while attached? Is this an easy task, or shall I plan so time to check the mechanism?

 

[bucyrusboater]

Re: What am I missing, Help required

Update!!!

I think I may have found the problem. Still going to check everything else. My engine lock was not locking the engine down in place in either forward or reverse. My guess, engine was bouncing and swinging in the water while going forward. This makes me believe that this could have been the problem. Wont know until, i get back into water. But will check fuel system< and need to replace bellows.

Will replacing the bellows be a task, and can I do them myself?

Thanks for all the advice.

John

 

[cooter2506]

Re: What am I missing, Help required

Outdrive will stay down in forward due to the thrust of the prop. So I dont think thats your problem.

 

[bucyrusboater]

Re: What am I missing, Help required

Update on current topic.

I have followed Don's check list in the adult thread:

Here is what I have done:

Tested Fuel system (Replaced fuel pump, and tested boat side fuel system, still did not correct issue)

Changed points, plugs, distributor cap, rotor (Set points, and Dwell, then timed system, still did not correct problem, but now I get 3500 rpm's at WOT)

Finally removed items to check timing marks. (Rotor is not pointing to number 1 plug, so felt timing might have slipped. only mark not right on is the cam shaft for distributor, seems to be off mark by 1 tooth. Went ahead and order new timing belt, and replacement gaskets needs. They arrive tomorrow, and hope the problem is corrected)

Just wanted to give everyone an update, and thanks for all the advise.

John

 

[bucyrusboater]

Re: What am I missing, Help required

Update.....

Put new timing belt on, made sure all marks were correct. I get about 4000rpm's at wot now.

When i get to 4000, engine sputters and backs down.

I cleaned carb lastnight, and have one question. I have a solex carb, and not sure 100 percent how the accelerator pump rod should be adjusted? The OEM does not explain enough about this adjustment.

I have it set now, so when you accelerate it has a steady stream of fuel coming from the j tube.

Any advice?

 

[bucyrusboater]

Re: What am I missing, Help required

I am out of ideas. I have checked everything in the "low RPM sticky", I have everything timed right on, no fuel issues. Compression is good.

This is the only thing I can think of now.

I am getting 4000 rpm's, and about 22mph. I have a 15x15 prop on, i know if I increase the pitch, I will loose rpm's, but will I increase speed? I am just planning out, and it seems like I am out of power.

I do have a big boat, for the size of engine, but replacing is not an option at this time.

21ft Bayliner Cabin Cuddy
AQ125/270

I am looking for about 35mph

Please help.

 

[71satellite]

Re: What am I missing, Help required

Hi there,

I can't offer a solution, but wanted you to know that I have the same issue. I bought an 86 Bayliner Capri 21 foot Cuddy (with the same engine and drive), and it also maxes out at 4000 RPM, and about 25 MPH. I replaced the entire ignition system (points, cap, rotor, plugs, wires) as part of a big tune-up when I bought it (this spring), and have checked for throttle plate operation (wide open).

I did adjust the outdrive trim tab after my last outing this past weeknd, as I've always thought it was pretty skewed to one side. I noticed that the steering was a bit "laboured" while driving around. I've only had the boat out 4 times, so I'm definitely still learning about it.

I haven't done compression tests or timing adjustment yet (haven't had a lot of free time). From what I've read; however, these boats should be able to manage 30-35 MPH.

I am going to clean the very light build-up on the hull, though I don't think that will be the magic fix.

Anyways, hopefully we'll be able to get the most out of our boats.

Chris

 

[71satellite]

Re: What am I missing, Help required

Hi again,

Well, here's the latest improvements after a weekend up north.

I did clean the hull (it wasn't overly encrusted to begin with, but it sure looks spotless now), and did play with the outdrive trim adjustment (it is at about 2/3 the angle that it was originally). I also put some carb cleaner in the tank when I topped it up with gas.

Now I'm maxing out at about 4400 RPM and about 26-27 MPH. A slight improvement, but I'll take it.

One thing I have noticed is that my trim tabs (Bennett trim tabs, installed by previous owner) seems to always be hitting the water, even when adjusted to the "fully up" position. They are mounted right at the bottom of the transom (parallel with the outermost step (chine?) of the hull). It almost ssems like they should have been mounted 1-2 inches above the bottom of the transom so they would be completely out of the water until they are moved downwards. I'll be pissed if that is the problem, as I sure don't want to move them and expose a bunch of screw holes.


Well, that's the latest. Hope it helps,

Chris

 

[71satellite]

Re: What am I missing, Help required

Hi "Bubba",

Thanks for the advice re: the trim tabs.

I've read quit a bit about the waterlogged-foam issue, but when I pulled up the floor to replace it, I didn't find any foam.

I replaced the floor from the cuddy to the rear seats/engine cowl (the long aisle and the "T" at the back", and when I ripped it up all that was underneath was the large aluminum gas tank, and the fiberglass hull.

I didn't remove the seats or the "bunks" that support them. In my boat, the seats sit on rectangular boxes with storage cubbies, and the cubbies themselves are on top of rectangular boxes. Is the foam beneath the cubbies? If so, it appears that I'd have to cut the boxes apart to access the foam, as the boxes are covered in a uniform layer of fiberglass everywhere that I can see (i.e. everywhere that isn't carpeted).

Here are a couple of photos illustrating what I'm talking about.


So....does my boat have foam hiding somewhere, or did it not come with foam from the factory? If I can shave a few hundred pounds of weight I'm sure that would help with the speed issue!

Looking forward to your reply,
Chris

 

[krisnowicki]

Re: What am I missing, Help required

I have a trophy with that set up and it is 21ft you wont get 35 out of that set up.
If you are using a 15x15 prop and you get 5000 rpms and no slip ( which is not possible )
5000 rpm 2.15 ratio 15p prop slip 0% = 32.7 mph
the most speed you will get is 32.7
But you can't run that engine at 5000 for very long before we start a post talking about how to bebuild you blown engine.
But you can run it at or below lets say 4000 and you get about 10-20 % slip ( slip is the effeicancy lost by your prop as it "cuts" through the water) and you you will be at
4000 rpm 2.15 ratio 15p prop slip 10% = 23.8 mph

 

[Glastron_V210]

Re: What am I missing, Help required

Hey there. I have a Glastron V210 (21ft) camperized with a hardtop and a 260 mercruiser (GM 350).

I can't imagine your boat being heavier than mine, and it does 40+mph wot with a 19pitchX14.5 I think.

Anyway, my comment is that with the trim on the leg right down, the boat does about 28mph, trim up and it does 40+. Now, I'm talking about the leg power trim, not the trim tabs. The idea is that the faster I go the more the boat levels out and the bow starts catching the water, increasing drag. When the bow is out of the water, the drag is dramatically decreased.

Trim tabs move the bow down, not up. Leg trim moves the bow up. Does the volvo leg have power trim? If so, try trimming it up a bit and see if it improves you speed (Your takeoff will be slower, and the bow will go up more on takeoff, be prepared for this).

Chay

 

[Glastron_V210]

Re: What am I missing, Help required

One more thing...from my car experience solex carbs are trouble. I'm not sure about the marine equivelent, but if nothing else works out consider 'borrowing' a carb set up for your engine if you can.

Chay

 

[71satellite]

Re: What am I missing, Help required

Hi Chay,

Thanks for your input. The Volvo 270 does not have tilt/trim, it locks in place in the "full upright position". Its really a pain when trying to get on a trailer and out of the water, as you have to raise the motor to clear the bottom/ramp, but then you can't use reverse.

Also, I noted you have a v8, I have a 4 cylinder... I think that has an influence too, as my motor can only push so hard. What surprises me is why the motor won't rev any higher at WOT.

I'm hoping to get a definitive answer on whether I should be looking for wet foam under the cubbies below the seats.

Have a great day,
Chris

 

[COBAY85]

I know these are old posts but I had this same problem with my boat. The prop would pop up when I was in reverse and then slam down when I shifted out of reverse. Also the light would always stay on. The problem with my boat was that the worm gear rod for the tilt mechanism was slightly bent. It happened due to my own ignorance of the way this boat is configured. The lift mechanism only pushed on the outdrive. There is nothing to hold it in place other than the water pressure as the boat is under way (forward). I was pulling a few people in a large tube and it was struggling to plane. My last boat had a mercruiser with trim and I tried raising the outdrive a bit as took off pulling people around. It worked great except that it puts incredible pressure on the worm gear rod and bent it. With the rod bent it would not retract far enough for the lock mechanism to work so when put into reverse the outdrive would lift itself out of the water. I wanted to mention all of these things so that anyone new to this outdrive can learn from my mistake. You should never be underway with the outdrive up on this boat except for basically idling in shallow water.​ The good news if there is any is that this part is easy to remove, to take apart and re-grease and I was able to find one locally from a guy who was parting out his boat.

 

[GA_Boater]

I know these are old posts but I had this same problem with my boat.

Read the Help Tip on top of the page before posting in an old thread. Then don't post, start a new thread. Thanks.

Closed.