1977 Mercury 1150, now boat on water, several problems

[tavacska]

After a few adjustment at back yard, I was satisfied with the motor running.
This is a rebuilt motor, almost for everything.
At back yard, it idles at rpm 900 with flush. Start is hard, even in 80F weather. About 30 seconds cranking, with throttle cable a little bit open. When starting, it roars to 2000 rpm, and I hold it to be 1400 rpm for 2 mins. Then it come to neutral and idles at 900 can last until the gas is used up.

However, on the water, it's another story.

1. Boat is leaking from the main hole. It's a 1977 Boston Whaler newport 17 in good condition. The manual said, the main hole is designed to be open, and the water in boat can disappear itself by this hole and no bilge pump needed at all. It is suggested to be open for this fantastic feature. I believed it.
It leaks water at the first moment the boat touch the water. I have to find a piece of cloth and stuck it there and use bucket and water bottle to drain it out of the boat. It's really a funny scene on the crowded ramp.
But my question is, the feature of the boat is respectable. Is there something wrong I did? The motor is 115 hp, and comes with the boat from the beginning. Is it too heavy at the transom?
But anyway, I am planning to install a bilge bump and a hole blocker as I was planning to.

2. Idle running.
The boat can idle at 900 rpm on land. But in water, it chokes and stops. The reason is in water, even in neutral position, the rpm can slow down up to 200 rpm.
This was expected. I turn the idle speed up to 1200 rpm. Can it can be idled at 1200 rpm in neutral position smoothly. But when I tried to engage to forward or backward, it chokes and dies.
So I have to turn the idle up again to 1400 in neutral, and when I engage it, I have to push it fast to some throttle position. It still can not stay long at the idle position when engaged, it's about 900-1000 rpm. This caused a big problem when I have to launch boat back to trailer.
The other problem, with 1400 rpm in neutral position, when I engage it, I can strongly fill the the moment engagement of the propeller. Is it bad for the lower unit at this high idle speed?

So in short, in neutral idle speed, 1400 rpm. Engaged idle speed, 900-1000 rpm. Can not stay long and will die at the engaged idle speed.

3. Starting problem.
It is very hard to start. I tight the pump, give some throttle, push the button for the throttle blockage, and then crank it. It takes 30 sec to 1 min to start it. In the water, each time start after 10 min no running will do like that. It drives me crazy and each time it starts, I feel blessed. Cause I don't have any other backup option to get back on land.

4. It runs great at 20 mph.
Very smooth and solid. But the tilt is not good. The bow part will raise a lot at 20 mph. So I dare not to put it at full throttle. I believe it could reach at least 30 mph.
I have a video of running, if you want to see it. I will post it here.


So the problem is idle and start. I cleaned the carburetor in detail. Especial at the idle holes. I sprayed fluid into the idle speed needle hole, I can clearly see the fluid come out from the two tiny holes behind the throttle gate. I paid a lot attention to the passage from the float bowl to idle speed hole as well.


Please give my your suggestions on my next step check.
Thanks.

 

[tavacska]

And in addition. I read some restrictors threads in the in-take air rooms. I installed those tiny restrictors in position. And I also punched the walls to keep the restrictors there permanent. People said it is good for idle, that's why I did it.

 

[jimmbo]

600 - 650 in gear is the idle speed. The carbs may be too lean. Is it firing on all cylinders? On the muffs you can have 3 of the 6 not firing and it will run.

The Hard starting... Are you squeezing the primer bulb till it gets firm? Are the floats set correctly?

Are you trimming the engine all the way down? Is there a tilt/trim pin? If so, is it in the hole closest tot he transom? Bow rise will be at its highest at about 16 - 19 mph



What restrictions are you referring to?

 

[tavacska]

Jimmbo,

1. The carbs is set to be 1 1/2 turn from slight sit. It was set at 1 1/4 before, and it is almost impossible to start. Maybe it's still too lean?

2. I don't really know if they are all firing. How to test it? But those spark all spark when I tested. And they are all new sparks.
Please refer to the link for the idle run I testes 2 weeks ago.
https://youtu.be/14KXTDQXjQE

3. I can not reach 600- 650 in gear on my current settings.

4. I squeeze very hard on the primer bulb and it gets firm. I can hear the fuel is flowing into the bowl. And I did replace all the bowl needle and seat, except for the floats cause they are intact. There are flooding before, but now it's okay. I tried to set the lever's height or distance following the manual. So I think the floats system should be good.

5. There are 5-6 tilt pin there. the last inner most holes are dirty and seems never been used. It was set to the outermost pin when I bought the boat. So it made me believe that the pin should be there. But in water test yesterday make me believe it is not right. I reset it to the 3 rd pin yesterday in water and run till the end of day. I think it still tilt too much. But I am not sure.

6. the restrictor is the same as shown here.

 

[Faztbullet]

You say it was rebuilt ...what was done?? A re-ring is not a rebuild

 

[tavacska]

I mean rebuilt by myself. Or rebuilding.
It was not done.
I will edit it to make it not misunderstanding.

thanks.

(well I am not allowed to edit the first post)

Basically, I do all the work by myself. Now I notice the "rebuilt" means like a remanufactured one and working in good condition.

 

[tavacska]

And one more thing, there is gas or oil floating around the motor when the motor stops. I noticed it too when it is running with flush.
I can smell strong gas when the boat is parked in the garage. Is that because the tilt make fuel running out of carbs?

 

[jimmbo]

The restrictions are part of the oil recirculating system. I can't recall if all the holes had them, or if only one did. Looking at the transfer ports, it looks like someone took a grinder to them.
Spark needs to be tested using a tester that has a gap of about 7/16".
1 1/2 turns out is an initial setting for the idle mix screws. However if the floats are set incorrectly and/or internal passages of the carb are dirty, setting a proper mix will not happen. You had the carbs off the engine? Is so, did you perform a carb to throttle sync check/adjustment? Where/what are you adjusting to set the idle speed?
Does the engine have power trim? If so them put the pin in the hole closest to the transom, if not, usually it is the second or third hole out from the transom
Some fuel does spill out when the engine is tilted up, incorrectly set floats will aggrivate the situation

5000 - 5500 is the full throttle range for you engine

 

[tavacska]

Jimmbo,

All sparks just tested. 1,2,3,5 are 7/16". 4,6 are 6/16". Maybe a little bit errors there.

Those transfer port restrictors have a good debate there. And the manual says to install those, so I install all of them too.

I agree I should do more on idle mix screws. Actually I did a lot. When I pass the 1 1/2. I can tell no difference. When they are set below 3/4, engine will choke, and then I set it to 1/2 more to 1 1/4, as manual states. But later I found out with 1 1/4, I can not start the motor. So finally, I set it to 1 1/2.

The carb and throttle and timing sync I did it following the manual, and Chris also gave suggestions. I think the sync should be ok.

When I adjust the idle speed, I adjust the idle speed screw. And then readjust the throttle cable connection at the engine.

Please enlighten me about the floats set up. I set it up following the manual strictly. I can confirm now, that no fluid will come into float bowl, if it is at full level. Do you mean, if it is set up too high, the bowl will be used up and no fuel will come in?


The only thing I can tell now is that the tilt pin is set up totally wrong. But I don't know how much it will improve the situation. I will set up a water tank and do the tune up at home.

 

[jimmbo]

If the level is set too high, or the needles/seat is leaking, fuel will come out of the vent orifice. If set too low, the fuel delivery to the main circuit will be delayed.

When the idle mixture screws are turned clockwise the mixture is leaned, counter clockwise richens.

 

[tavacska]

Hey, guys,

Here is some feed back.

The starting problem is solved. It turns out to be the idle mix adjust is too lean. The manual says starting from 1 1/2. My final settings are 2 1/2 in gear. 1 1/2 is good for idle in flush. But in water tank, it should be 2 1/2 for idle alive. And 1 1/2 is too lean for starting also.

Now, with the current settings. I just need to push the throttle button and crank for 5 sec, this is to make gas into the throat. Then cranking with throttle a little bit open, it will start within 10 sec, or even better. Not much chance for starting from a long sit.

The hot start in between, is absolutely instant.
I am very happy for this , and thanks all for suggestions.

Question:

Now my rpm is reading 950 in water idle, 650 in gear in idle in water. ( if my tachometer reads right).
But whenever I shift to forward or back, I can still feel the clunk moment. Is that a normal thing?

When in forward idle gear, I still feel it's faster than what I need when I do my launching.

Edit: in addition, it won't die, when I put it in forward gear. But if I slow down from a fast speed, and put it to neutral, it will die without choke. I think, it is caused by the more resist from water from behind when slowing down?

 

[jimmbo]

There is going to be clunk when you shift, the design of the shift mechanism is on of, 'it is either in or out of gear'. There is no clutch to slip, so don't 'ease' it into gear. That only causes expensive wear. Just quickly shift it in and out of gear. 650 rpm is ok, I think the spec was 600 - 650.

 

[tavacska]

I noticed when I push forward, it will get engaged very good.
But when I pull backward, I will have to pull always noticeably farther to avoid the grinding of the gear.

I think maybe I have to readjust the gear cable at the engine.

 

[demarko210]

tavacska

I had the same problem last year with my boat. I could not leave the dock. Keep listening to guy on forum same 650 in Forward gear. I keeps saying I cant get into forward get it would choke out. Now that I am rebuilding the transom of the boat this year, I thought maybe I would turn my air mixture 2.5 turns instead of listening to the manual 1.5. Everyone was telling me 1.5 cause thats what the manual states. Sometimes you need to turn more. I will see after I get this wood back together.
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