Confused?

[yago]

Have just bought a 18 foot thunderbird boat. Has ag120b with a 270 merc stern drive. MAn i boght it from thoght he was a mechanic. I found out. Re done cooling system, seals, impellor. Tuned it up. The timing was set on #4 cylinder. Question. Have pdf manual. Shows to different settings for valve adj and timing. One is 6" btdc at 750 rpms. The other is 10" btdc at 9000 rpms. The other question. Valve adj. It states/ Clearance-when adj-Intake or Exhaust. Cold-010-018". Hot 012-020". Then below it the same thing again. Cold014-016".-Hot 016-018". I allways set my valves on cold. Is the top one intake botttom exhaust. need a little mech help. Thank You Yago.

 

[Bondo]

Re: Confused?

Has ag120b with a 270 merc stern drive.

Ayuh,...

Do you have the motor,+ drive Serial #s,..??

You do Not have a Merc...
It sounds like a Volvo, but you need to be Much more Specific....
Hence,... Give Us a Serial #...

 

[Maclin]

Re: Confused?

Sounds closer to a Volvo Penta AQ120B with 270 drive doesn't it.....

 

[chiefalen]

Re: Confused?

yea what Maclin said.

 

[captmello]

Re: Confused?

Assuming you've got the AQ120b Volvo Penta.

I looked up your motor on the VP website.

Timing, according to the operators manual for that engine is 10 Deg BTDC. and the valves COLD are .014-.016 intake and exhaust. The other numbers are Check, whatever those are. Perhaps if you were to check them and find them in the .010-.018 range they would be okay.

What Manual do you have that says 6 deg BTDC? Did you get the manual here on Iboats?

1978 model year?

Please be specific.

Good Luck to you!!

 

[Don S]

Re: Confused?

Bet it looks like this, and it's a Volvo outdrive, not Mercruiser.

Here is a picture of an AQ125 with a 270 drive. Your drive should look like it. The engine will look similar.