4.3GL PWTR won't go over 2500 RPM... Help please

mr_carman007

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Hello and thanks for helping me out.

On my original voyage the tach went up pretty high like there a spun prop hub/bad coupler... Since then I have determined that my tach isn't always the most accurate since I have run it in my driveway to determine if I had properly repaired the cooling system. today I took it out for its second voyage (under my ownership), it cooled like a champ and the rpm gauge functioned properly, with the rpm gauge functioning properly and with a friend listening to the motor we ruled out a bad prop or coupler.

The problem I'm running into is the motor wont produce more than 2200-2500 rpm depending on trim. The motor runs nice and smooth at all rpm range... Just won't go above 2500. I took the water separator off and dumped the contents into a glass jar, it contained no water whatsoever. What would be the next thing to check, the timing or the fuel pump? Is there something that I am missing that is an easy fix?

Thanks for your help!
 

alldodge

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I would start first with a compression test, you could check fuel pressure (4 to 7 psi) but not really thinking its fuel. Have you checked timing and spark plugs?
 

mr_carman007

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I have not checked timing or spark plugs yet... I've never messed with timing before, is it easy or should I get a mechanic to take care of that aspect? What tools do I need besides a timing light? As for the spark plugs, what should I look for on those?
 

alldodge

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Not a VP guy, just noticed no one responded yesterday to thought I try to help. Looked up your motor and it shows part number 21513423 which goes to from a DonS post
You need either the OEM GM plug AC-MR43LTS or the NGK-BPR6EFS plug. gap at .060 per link below
https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-20-36038.aspx
Volvo plugs are here
http://www.ebay.com/itm/VOLVO-PENTA-SPARK-PLUG-KIT-SET-OF-6-21513423-/181813669454

Figuring your timing should be at 8 BTDC like Merc's but unsure. Hope a VP dude comes to verify. I would let a mechanic do it unless you can verify what I'm listing.

To set timing it appears the engine has the Delco EST distributer so look for a Purple/white wire coming out the distributer which would need to be grounded. Grounding the wire to put the engine is base timing mode. Once in base timing set timing, lock down the distributer, verify timing has not changed and remove jumper
 

bruceb58

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mr_carman007

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Thanks for the help guys, I think the boat may be ready to rock and roll now!... here is the store:

So I got my timing light in, but was having difficulty timing it properly with the light (found out why later) so I decided to take it out and time by actually taking it on the water and adjusting as while out there. I got it to go 35mph but couldn't get it over 3500 rpm, it started to get dark so I decided to call it a night. Over the weekend my neighbor came over and we started looking at it again, we found the timing marks on the harmonic balancer and timed it properly with those... boat when timed properly the boat ran like total sh*t. At that point we started thinking that whoever the previous owner had replace the distributor, plugs, and wires had maybe not attached the plug wires to the proper plugs. We re-ran all wires to the proper cylinders and started it up... it is now timed out properly and is running smoothly in my driveway so I am going to take it out tonight and test it, I've got my fingers crossed this does the trick!
 

bruceb58

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Did you use a timing shunt to set the timing? If you didn't use the shunt, buy one. Don't run the boat until you get it timed with the shunt.
 
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mr_carman007

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I couldn't find the timing shunt so we timed it without it. I took it out yesterday, the boat ran the best it has run so far however it still isn't perfect. I am going to find the shunt when I get home tonight and retime.

How many RPM should I be reaching in this boat? I am unsure of the prop pitch, however it is a VP 4.3GL PWTR. With boat trimmed a little below half way, and WOT I am seeing about 4100-4200 RPM which seems a little low to me. I am assuming this will change once it is timed with the shunt though.

Is it bad that I ran the boat after timing it without the shunt?
 

mr_carman007

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I did buy it, I need to find it in my garage though... already misplaced the damn thing lol.
 

mr_carman007

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Alright so I found the timing shunt. Just to confirm how to use it, does that clip need to be grounded out or hooked up to 12v? I also wanted to confirm that the 3 nipple looking dots on the harmonic balancer ARE the proper way to time out the engine and also I wanted to check how to find out how to determine the exact degree of advance/retard on the harmonic balancer.

Thanks!
 

bruceb58

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Go to my post #5. There is a link to the manual and you go to section 5.

Clip goes to +12V.
 
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mr_carman007

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Ok so before I take it out again I want to make sure I timed the ignition correctly. I put the timing shunt on the distributed and timed it to 1 degree btdc, I took the timing shiny off and took another reading... Approximately 18 degrees btdc at about 1000-1100 rpm (was previously at 600 rpm prior to shunt being removed, once removed the rpm rose up to 1000-1100).

I'm planning on testing it at the lake very soon as the daylight is running out here, please let me know your thoughts.

Thanks,

Steve
 

mr_carman007

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Ok so before I take it out again I want to make sure I timed the ignition correctly. I put the timing shunt on the distributed and timed it to 1 degree btdc, I took the timing shiny off and took another reading... Approximately 18 degrees btdc at about 1000-1100 rpm (was previously at 600 rpm prior to shunt being removed, once removed the rpm rose up to 1000-1100).

I'm planning on testing it at the lake very soon as the daylight is running out here, please let me know your thoughts.

Thanks,

Steve


Sorry for the improperly spelled words... Autocorrect got me again!
 

mr_carman007

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Aug 9, 2015
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Did you use a timing shunt to set the timing? If you didn't use the shunt, buy one. Don't run the boat until you get it timed with the shunt.

Took the boat out today, it ran awesome! Boat speedo got up to almost 50, gps speedo said 41 very thankful for you Guys help on timing!

So the old saying - boat stands for "bust out another thousand".... Well today one of the Pistons in the steering rack began letting a lot of power steering fluid (dexron ATF). Is there a seal kit I can buy to rebuild this or is it one of those situations where I have to purchase another rack?
 
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