Old AQ125 has not run in years

[kamby]

Re: Old AQ125 has not run in years

Ouch, for the heck of it you might want to try pouring some marvel mystry oil into the cylinders and letting them soak, could be the rings are dry from sitting. You got nothing to lose, i heard of people actualy unlocking frozen motors with that stuff.
Otherwise yes your looking at a rebuild.


Mines been running pretty strong too, mine was built in 1984 that last year volvo used the 125a engine. If memory serves the compression numbers were 160+ accross the board from the Previous owner. It will do about 30-35mph on 3/4 throttle 4k rpms.

 

[proshadetree]

Re: Old AQ125 has not run in years

If you really want to boost compression take hot cooking oil and put 3oz down cylinders.If you know you have it timed right it will start.When the cooking oil gells it will seal a cylinder with no rings.After it starts let it run so I hope you got it on the muffs.When it warms up,pray.Ive seen engines with stuck rings freed up this way.Might also check valves.If they are sticking wd40 or pb blast and a pry tool will normaly work them free.Best of luck

 

[kamby]

Re: Old AQ125 has not run in years

Thats an interesting trick, i'll have to try that sometime. But if it starts and run with the cooking oil in it, wont it blow out the exhaust? I know someitmes if you can get a low comp engine to start, the rings may come back to life. If u do get it to start might wanna put some sea foam down the carb throat too help clean the intake and valves, just be sure to be clear of the exhaust, that stuffs strong.

 

[rucaradio]

Re: Old AQ125 has not run in years

From what I understand it's not necessarily the PSI you get with a compression test, it's how close each cylinder is to eachother in terms of PSI. Although it's not good that you're under 100, it may be stuck rings.

I've got a 131d and my comp. test was around 140 (+/- 5) psi.. These Volvo 4-bangers are good motors and generally pretty bulletproof. I'd squirt some MM oil into each spark plug hole and let it sit for a day or 2.

 

[freeboats]

Re: Old AQ125 has not run in years

Lots of good advice again.

I was thinking of trying some MM oil in the cylinders, now I have comfermation

that it could work, so I ll do that right now.

I will get some PB blaster for the valves in the am

by cooking oil like crisco, somthing solid at room temp?

I thought I would also try some 20-50 wt oil to increase compression,

Good idea??

 

[airmail]

Re: Old AQ125 has not run in years

First thing. Is your battery charged up? Does the motor crank over fast? Are you letting it hit 4 or 5 times with the compression tester in the cyls?

Crank the motor over till the tester stops rising. Also open up the carb all the way when you are cranking it over.

The lifters could have bled down over the years. Might take a little time to get them up. I wouldn't be real fast to over haul just yet.

The numbers you have wet are good enough to get the motor to start. But everything else needs to be right.

One other thing. Be very careful while trying to start this motor. If you have to much fuel in the intake it can backfire. Be sure you have a fire extinguisher handy and make sure you are not alone and stay away from the top of the carb. A friend of mine was burned very badly from a backfire while working on a gas engine. He was alone in the country with no water or extinguisher.

 

[kamby]

Re: Old AQ125 has not run in years

Good advice airmail. these are down draft carbs so they have a straight shot to the intake, and when they back fire, poof straight up. There should be a fire extiguisher on the boat at all times anyway, I have 2 on mine.

To start the you might have to get some fuel into the float chamber by taking the top of the carb off, then you just pump 2-3 times with the throttle and crank over. These are cold blooded engines and need to be warmed up before running at high speeds. They run hot too thermo wont start opening till 180 and fully open at 190. Make sure your running on muffs and the bottom hole on the drive is plugged up too.

 

[proshadetree]

Re: Old AQ125 has not run in years

Crisco get it hot If your not putting it in the plug hole.about 1 cup with the engine cranking over good down the intake.I like the 3 to 4 oz down the plug hole.I normaly dont do the pb blaster to valves till I cant get to start or have 1 stuck with the engine running.Pull vale cover and spray stem through spring.Pry them down and if they hang down pry them back up.

 

[freeboats]

Re: Old AQ125 has not run in years

hey all, I am gonna start a new tread cause this one is too long