Aq131A Video Please Help

[Brucetafer]

Ive wasted hundreds and hundreds of dollars for "mechanics" to look at it, and they all throw up their hands and say well uhhhh, we can try this... well im tired of throwing money away...

http://www.youtube.com/watch?v=ft6XiEbx1D4

ive cleaned the carb,
timing set at 6* and mechanical advance works (cleaned out the dist)
does not have new wires, nor dist cap, they look good and PO said they were less than 5 years old...
brand new filters, brand new fuel...

im thinking its a sticking or floating valve... what do you guys think??

 

[Don S]

Re: Aq131A Video Please Help

Do a compression test, and a leakdown test.
What is the condition of the points, and what is the dwell set at?

 

[1fishbone]

Re: Aq131A Video Please Help

timing set at 6* and mechanical advance works (cleaned out the dist)
does not have new wires, nor dist cap, they look good and PO said they were less than 5 years old...

The only way to determine the mech advance is working is to have it curve tested...they test at recommended rpm

Wires/dist cap/rotor...5 years on a boat is closer to 10 years old.

Ignition wires touching the engine might be grounding out.

Check valve lash and while there, check timing.
Timing marks and actual time can be different!

Not enough back pressure....too much back pressure.
(I've seen people try to make copper or stainless exhaust)

#1 Accelerator pump...it might be sticking

 

[Brucetafer]

Re: Aq131A Video Please Help

sorry for the long wait, the ignition is a pertronix kit, so no dwell, thats why i bought the pertronix, i figured it was spark,

the wires will be changed soon, xmas is xpensive!!!

per a volvo tech, he said the timing advance per rpm was pretty much dead on from the timing mark, but then again, he said the mark may be off... how the hell am i supposed to know what actual timing is?? i found the timing mark by doing the tdc test and brushing away rust...

the compression is 180 at all 4 at 5 cranks each wot...

leakdown test hasnt been performed yet, shocking i know, 3 mechanics and 1 retard didnt go there...

ill check the rebuild again, its all original solex or volvo parts from the po rebuild 5 years ago, ive heard bad stories about cheap rebuilds... accel pump seems to be fine, not sticking externally, but who knows whats going on inside...

thanks guys, and keep the thoughts coming!!

 

[dockwrecker]

Re: Aq131A Video Please Help

I watched your video repeatedly and I keep thinking the blowback through the carb is a weak/cracked /broken intake valve spring, which essentially is floating slightly at above idle RPM. It would compression test in a static condition, but floats open slightly under power and remains open upon deacceleration, thus the backpressure through the intake. I have no other explanation for the blowback. I couldn't hear a classic "lean miss/backfire" in your video that would be an indicator of starvation or a low float condition. It idles well and I don't hear the classic starve "cough". Maybe something to look at.

 

[Brucetafer]

Re: Aq131A Video Please Help

thanks for the quick reply, ive watched the video about 20012938 times, im guessing bad or sticking valve myself as well. i just dont want to deal with that... bah... i guess i can check it out also... anything else i can check while im in there?

 

[dockwrecker]

Re: Aq131A Video Please Help

Short of pulling the cam and lifters and replacing the pushrods, nope.

 

[FreeBeeTony]

Re: Aq131A Video Please Help

My guess is a sticking intake valve or corresponding lifter.

I had a similar problem on a V8...had fuel spurtting out of the carb at high RPM's (~3200).

It did not show up in a compression test.......I finally found out what cylinder it was by shorting out the plug wire at the higher RPM under load.

I replaced the lifter and readjusted the valve lash but the problem came back while under way.....lifter hung up holding valve open, kissed the piston and you can guess the rest....

Hope this helps.......good luck!

 

[sqbtr]

Re: Aq131A Video Please Help

Can't see the video at work, but, from the description I would be checking the cam timing.

No lifters or pushrods on that engine.

Valve lash is set by shims on top of the followers.

Saw the video tonight, looks like good flow out the dump tube. 10 to 1 the cam timing has jumped a tooth.

 

[Brucetafer]

Re: Aq131A Video Please Help

cool deal sqbtr, im hoping your right... but some guys said that the motor wouldnt even run or idle for that matter.... that would be freaking awesome due to the fact that i have a cam seal leak and all brand new timing belt and gaskets?? i think thats the first thing im going to do when i get her out of the shop..

wheres the best place to get all the orings and such for the heat exchanger?? or do i dare use the ones that are in there??? thanks!!!

 

[GLENN M]

Re: Aq131A Video Please Help

sparkplug wires,check with ohm metre

 

[sqbtr]

Re: Aq131A Video Please Help

The seals should be available here at i boats.

Replace the tensioner while you're in there, the automotive ones are the same.

Do check the valve clearance, an old volvo car guy should have the shims and tool to install should you need adjustment.

If #4 is out of adjustment, pull the ex manifold to check the exhaust port.

 

[CharlieB]

Re: Aq131A Video Please Help

Double check cam to crank timing, if the belt tensioner is not set perfectly per the service manual directions it is too easy for it to jump a tooth.

 

[Brucetafer]

Re: Aq131A Video Please Help

thanks for the tips guys, the volvo mechanics here are straight old and dont want anything to do with my boat... they said pull the motor and bring it to em! lol....

anyhow, im going to get new wires, and start pulling the heat exchanger off and just get at it...

ill post results as soon as i can..

 

[Brucetafer]

Re: Aq131A Video Please Help

so took it to volvo penta, and the main guy there said its a bad head, i laughed in his face after he said this, so my first reason was where does he think after visually looking at this engine he can tell its a bad head.... then i come to ask well what part is bad? is it warped? or cracked?? he said well your not getting any compression out of cylinder 4... so instantly knew he was lying out his *** and so i played along with it...

my question: how much is this going to cost??

his response: well ive got a newer motor i pulled out of a wrecked boat, its a aq 151 and it will bolt right up... itll take me 2 weeks to do the swap and hell make sure its all running good for $5,000....

my response: (in my head) this guys a complete ****...

so im out of options here locally, i live in monterey california, and theres only 1 dealer around that i have not been to and its a hundred miles away...

where should i start looking for people?? is there anybody on this forum that would like some cash thats somewhat local to me?? i dont mind driving, i just want my damn boat fixed...

 

[tbear1964]

Re: Aq131A Video Please Help

$5000? I can't wait to part out my boat. I'm gonna be rich! LOL

Total bummer for you. Good luck on your mechanic search....

 

[PiratePast40]

Re: Aq131A Video Please Help

I"m surprised you found a dealership that would even look at it since it's so old. The engines haven't been produced since 89' so you're at the mercy of the market in your area. The unpleasant truth is that you either learn to work on it yourself, buy a newer boat, or pay the going rate for a pro to do it for you.

Not sure that I'd be too interested in the more complex engine (DOHC 151) since it's used and head parts will be even more expensive that for your 131.

 

[Brucetafer]

Re: Aq131A Video Please Help

Well the harsh truth is the mechanic that I know and trust straight said it's going to be a ton of money, and also said the motor isn't
Worth working on, so I'm pretty sure I'm gonna have to learn on my own... A buddy of mine rebuilt a aq175, and said hed help
Me, do you think that that motor and mine are close enough to work on and he'd know what to do??? I'm pretty sure I need a bunch of parts, but I don't know what can be replaced since these parts seem to be obsolete...

 

[captmello]

Re: Aq131A Video Please Help

It doesn't cost much to break the upper part of the engine down and at least take a look. You could do it with the engine still in the boat. How can these guys tell you its a bunch of money without knowing whats wrong??
Or do you already know whats wrong????

 

[Don S]

Re: Aq131A Video Please Help

If you are going to attempt the repair, you are going to need the proper service manual, so here is a link to download the OEM manual
http://www.4shared.com/file/64741910/25295432/230_250_251_131151171.html
Since you do have 180 psi compression on all 4 cylinders, I would verify the timing belt is on correctly and all the timing marks are where they should be and then recheck the distributor timing.