Splashdown, Yes .. but Throttle not quite right

[pantaloonz]

Hi All

First boat summary: 1986 Bayliner Capri 125 HP force 1254X6B

So my splashdown was "mostly" successful. I got water bleeding in from somewhere.. not enough to scuttle her or anything but there is some water in there

It started easily, but was dying going into gear, so I popped the top (I brought out tools) .. .. reset the idle mix again (1 and 3/4) is where I landed.

I then turned the idle up just a little bit to get it to stop stalling coming into gear.

That fixed the starting issue, and the stalling issue. It will go well enough to 1/2 throttle. After that it goes into what I'm calling a sine wave revving.

Vrrrrrr-RRRRRR-rrrrrrr---RRRRRRR--rrrrrr--RRRRRR it does this for about 5 - 15 seconds, then will eventually catch and immediately rev up, hold, plane out, and then I can cruise pleasantly, any back off of the throttle and the exact same thing happens, when trying to throttle up. It's quite repeatable.

Thinking maybe fuel pump? - it does sound to me like some sort of fuel problem

Whether I throttle up slow, or throttle hard, it will struggle each time at 3/4 - WOT and make this funny inconsistent rev.

In Franks sticky he mentioned "sagging, then recovering, then catching" and suggests the mix is too lean, this is the behavior I'm seeing except that the sagging/recovering repeats itself multiple times before catching on and going (maybe that is exactly what's happening?).. could this still be a air mix issue?

Thanks!


-Devon

 

[Jiggz]

I'm assuming you have the clear fuel filter between the fuel pump and carb inlet. Is it staying at half full or emptying? What about when it is whining, does squeezing the primer bulb makes any difference?

Are any of the plugs fouled? If yes, you need to back off the idle mixture screw to about 1 1/2 or 1 1/4.

 

[jerryjerry05]

The air/fuel mix only affects the low speed operation.
​Try cleaning the high speed jets.
Does the ball pump up hard before you start?
Backfire?

 

[SkiDad]

the primer bulb test Jerry mentions will let you know if your floats are closing the needle and seats.

 

[jerryjerry05]

It also will tell if the diaphragm in the pump is damaged.
It won't firm up if there is a hole in it.
It will just pump fuel into the 3rd. cylinder and cause a misfire/ backfire.

 

[pantaloonz]

Hi All I will try and answer these in order:

1. I have not installed the inline filter; that is something I will do. It's a great diagnostic point.
2. I will check the plugs; I've been away a couple days.
3. The primer bulb does stay very firm during start up. I have not tested it during the sagging/whining: I will and I'll post results.
4. I got a couple backfires when I first started her after her 5 yr nap: hasn't happened since.
5. I picked up some fuel system cleaner to run through it (would you recommend this?)
6. I need to research the high speed jets cleaning; can I do this without removing the carbs? ..

Thank you everyone. I'm on vacation this week (sorta) I hope to run this through several more tests. Is there any danger in going to WOT while on muffs?

I did notice one final issue that may not be related: on my four winns the prop spins freely, on the bayliner not nearly as easy. I have not had any problems shifting in and out of gears, or any problems holding forward or reverse.

Best wishes!
-Pantz

 

[jerryjerry05]

My opinion. fuel system cleaners. NO
Do it as a treatment and then don't worry about it.
​I mix 1/2 gal of gas with a jug of Chevrons fuel system cleaner."Chevron with Techron"
​In a portable tank.
​Add the right amount of TCW3 and hook it to the motor and run it for a while.
This cleans any GUNK or residue build up.
​Does not remove dirt or pieces.
It gets to the hard to reach paces.

The jets can be reached by removing the bowl.
They can be cleaned out with a tip cleaner or tiny piece of wire.

​The bulb should loose pressure after starting.

 

[SkiDad]

Hi All I will try and answer these in order:

5. I picked up some fuel system cleaner to run through it (would you recommend this?)
6. I need to research the high speed jets cleaning; can I do this without removing the carbs? ..

Thank you everyone. I'm on vacation this week (sorta) I hope to run this through several more tests. Is there any danger in going to WOT while on muffs?

Best wishes!
-Pantz

5 - Quickleen is safe if you put in the recommended amount, I've used it - I didn't like sea foam. I have also used Mercury Power tune spray if you just want to de-carbon. I agree with Jerry on this - if you run the engine regularly you don't need any fuel additives.
6 - you can drop the carb bowls and get to the jets there - they are right in the center where the bowl screw goes

DO NOT run WOT on muffs - i would not go above 2000 and only in neutral.

 

[pantaloonz]

Hi All,

Phew, lots going on and very little boat time. -- I do have good news to report.

Checked the plugs - looked fine. though I haven't been running it a lot..
Took off the bowls, cleaned the jets: thanks for the bit of advice.
I did add fuel injector cleaner to the fuel tank (sorry didn't read the don't use additives part)
Reset idle mix screws back to 1 and 1/2, backed down the idle a little it was idle'ing at 1100

Took the boat out with a buddy, after a little warm up.. it ran pretty damn nice.

One thing I noted.. this boat is SOOO much lighter than it was it's a very different feel. I had my buddy (my size) sit in the bow for a hole shot, and we did just fine.
there was just a bit of the "wavy" idle but after trimming and planing out (like 2-3 seconds) all was good. -- My four winns probably weighs twice as much.

The boat does above 40 at roughly 4100-4400 rpm planed out, topped off around 45.. Which made me quite happy.
No leaks, squeaks or moans

Thank you: Jerry, Skidad, and Jiggz, you guys rock!

I consider this thread closed.

just for giggles; here's a before and after..



-Pantz

 

[SkiDad]

nice work !

 

[jerryjerry05]

Looks good.
Glad to help.