What is initial timing on 4.3GL & can I advance it to improve performance?

aimlow

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Hey Lou..Ibobi gave me a 3 month vacation. Screw THT. Friends on the site talked him down to 2 weeks. "Inciting violence". All I did was paraphrase a line from "Full Metal Jacket".
 

Lou C

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really?
I got yelled at on the allpar . com board for calling the Fiat 500 a clown car. LOL.
There are more inboard experts here anyway. THT slavishly will buy any over-priced alu outboard as if they are the only means of marine propulsion. One look at the parts prices tells you the OB manufacturers got the world's best racket goin' on...
 

tpenfield

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really?
I got yelled at on the allpar . com board for calling the Fiat 500 a clown car. LOL.
There are more inboard experts here anyway. THT slavishly will buy any over-priced alu outboard as if they are the only means of marine propulsion. One look at the parts prices tells you the OB manufacturers got the world's best racket goin' on...

Totally the best racket those outboards, although I do like them. . . Recent experience from a family member . . . Yammy F350 powerhead (i.e a long block) replacement . . . $20K :eek: :faint2:

I think I could have gotten a brand new 8.2L bobtail I/O engine for that. Comparable HP I/O long block would be about $5-6K
 

Lou C

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I like the lowered maintenance of OBs but not the repair cost....if buying an ob boat it would have to nearly new 3/5 years old.
and its not just cost it’s also complexity of the power head....
 

aimlow

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That's a lotta mass hanging aft of the stern. At least i/o's have that chunk of iron inside the boat.
 

GA_Boater

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This thread topic is: [h=1]What is initial timing on 4.3GL & can I advance it to improve performance?[/h]
 

GA_Boater

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And the question is..WHAT is a "GL"? Injected? TBI? CSFI?

When did the OP ask that question? This thread got thrown to the 4 winds.

It's been over a week since he posted in this thread. Please stay on topic.
 

aimlow

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the answer is NO simply put.

This. Too many unknowns. Lou's got hands -on experience with these engines. Although they share many components with a 350 SBC, there are enough items unique to the smaller version to make a broad generalization.
 

USA_boater

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Well I think with all the uncertainty I am just going to leave it alone...I might check it to see where it is set at the very least but its too cold for that right now...wish I had indoor storage! I just would like to know for sure if 87 octane is acceptable...I am guessing the carb motor has no knock sensor.
 

Scott Danforth

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87 octane (R+M/2) is what is in your manual.... your good to go.
 

aimlow

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Well I think with all the uncertainty I am just going to leave it alone...I might check it to see where it is set at the very least but its too cold for that right now...wish I had indoor storage! I just would like to know for sure if 87 octane is acceptable...I am guessing the carb motor has no knock sensor.

Probably not. Plus, you usually don't hear detonation "at full chat". It's better to be 2 degrees too retarded than 2 degrees too advanced.
 

Lou C

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Agreed and it is a good idea to pull your plugs out after a run, once a year to check the color of the center insulator. The window inside your engine. If they are nice and light brown or grey you are good. Blistered white is no good.
And while we are talking about timing and fuel octane the other factor in your inboard engine longevity, is correct prop pitch. You want that engine to be able to reach its specified RPM at WOT, if your rpms are too low, that engine will labor to pull the boat up on plane every time with the resultant overheating of exhaust valves and eventual low compression. When I got my boat it had a 14.5x19 on it and only got 4200 rpm. I went first to a 15x17 that got me to about 4600 and am going to try a 15.5x15 next to see how close to 5,000 that gets me.
 

USA_boater

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Agreed and it is a good idea to pull your plugs out after a run, once a year to check the color of the center insulator. The window inside your engine. If they are nice and light brown or grey you are good. Blistered white is no good.
And while we are talking about timing and fuel octane the other factor in your inboard engine longevity, is correct prop pitch. You want that engine to be able to reach its specified RPM at WOT, if your rpms are too low, that engine will labor to pull the boat up on plane every time with the resultant overheating of exhaust valves and eventual low compression. When I got my boat it had a 14.5x19 on it and only got 4200 rpm. I went first to a 15x17 that got me to about 4600 and am going to try a 15.5x15 next to see how close to 5,000 that gets me.

Great point Lou...on my list...the boat has an aluminum 3 blade but the PO gave me an un-used 4-blade with the boat when I bought it...He told me he had work done on the prop/skeg from a shallow ramp accident but I have no idea if it is still using the OEM Volvo prop w/ correct pitch...The tach doesn't work though so I have to figure that out first. I can tell you "on principle" I was planning to get a whale tail but since the boat gets on plane just fine I dropped that plan...hopefully that speaks to using the correct pitch prop when RPM is unknown.
 

Lou C

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Well I'd say your first priority when you start next season, is to have a working tach, because otherwise you will never know, if the prop is right or not. And while people worry about plugs, carbs, converting points ignition to electronic, etc, the MOST important adjustment so to speak on a marine engine is the RIGHT PROP. Without it reaching the proper wide open throttle rpm, the life of the engine will be shortened, because a low WOT rpm is like making a truck with a 2.73:1 rear axle pull a heavy trailer, starting in second gear. In other words NOT GOOD!
 

USA_boater

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Well by the way it gets on plane and the way it screams (sound not MPH) at WOT, I'd say it is giving all it has...BUT, I've only seen 43mph (full gas, people in boat other than me, gear, etc.) and I figured this 4.3GL should be capable to run 45-50MPH??? The lack of MPH is one clue that makes we wonder about the prop. I need to GPS the speed next season to know for sure.
 

Scott Danforth

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Well by the way it gets on plane and the way it screams (sound not MPH) at WOT, I'd say it is giving all it has...BUT, I've only seen 43mph (full gas, people in boat other than me, gear, etc.) and I figured this 4.3GL should be capable to run 45-50MPH??? The lack of MPH is one clue that makes we wonder about the prop. I need to GPS the speed next season to know for sure.

you may need more motor.
 

USA_boater

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I found some fast facts guide by Four Winns from 2004 online and it said the 4.3GL in this boat yields 47-50mph so either my speedo is off, the guide is off, or the prop is off?
 
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