AQ-131 Compression Test (Cont'd)

[scotttu]

I use Scott AT Work because I post at work mainly...<br /><br />Volvo AQ-131D, 275 outdrive...WTO of 3200, recall this conversation..<br /><br />Anyway per you all I went out to my boat today after work, pulled all plugs (They all look great!), inserted compression tester into each cylinder, one at a time, ran the test twice and came up with these numbers, this concludes so far that the head is not damaged I assume, although I am going to replace the exhaust manifold anyway:<br /><br />1 - 175<br />2 - 180<br />3 - 175<br />4 - 175<br /><br />Not bad, consistent as all get-out.<br /><br />So, back to the topic, my WTO is 3200 rpm, maybe 3500.....<br /><br />Anyone got the timing specs (10 degrees before TDC?)<br /><br />I am feeling GOOD about this, means I won't have to sell the boat or sink a ton of money into it <br /><br />When I bought the boat the owner told me that he put a lower pitched prop on and i might want to get a higher pitched prop if I was going to be running higher speeds...that may explain the WTO of 3200 rpm.....<br /><br />And the accelerator pump is not pumping gas, need a rebuild on the carb probably since it sat for 2 years....<br /><br />I'm excited because this is all small maintenance compared to replacing the head or rebuilding it.....

 

[Dunaruna]

Re: AQ-131 Compression Test (Cont'd)

A higher pitch prop will reduce your WOT RPM's even further.<br /><br />Fix the carb, do the tune, then think about props.<br />Comps look o/k.<br /><br />Timing: 6 deg BTDC @900 RPM (idle)<br /><br />Point gap: 0.016", dwell: 62 deg -+ 3.<br /><br />Your WOT RPM's are 5000.<br /><br />Aldo

 

[Don S]

Re: AQ-131 Compression Test (Cont'd)

If the engine has been running good, you might want to check your outdrive gear ratio. People (Former Owners) buy wrong drives and install them all the time because they were cheap. May not be the right ratio but they can go boating.<br />Try this.<br />Pull all the spark plugs (makes the rest of the job easier) then put the drive in gear and crank the engine over by hand until the propshaft turns exactly 1 revolution. Then let me know the outcome of how many turns and partial turns you get on the crankshaft.

 

[scotttu]

Re: AQ-131 Compression Test (Cont'd)

Don - Will do but it will be a few days before I can get back to it, maybe by the weekend....<br /><br />No points in this engine - that's also got my attention, appears to be an aftermarket (or factory?) electronic ignition in place of the points.....<br /><br />And Pitch - OK I got that backwards <br />I will have to take a pic, it's pretty obvious I think...<br /><br />thanks guys!