1998 3.0L Volvo Penta Mid-range RPM Engine Stumble

bergadam

Seaman Apprentice
Joined
Mar 27, 2011
Messages
31
I hope someone can help me, I am about fed up with this boat. I have purchased a new (not Rebuilt) 3.0L Vovlo Penta replacement engine for my 98 Glastron. I completed the first period of break in including setting the base timing to 2 degrees atdc and checked the advance which appears to be around 15 degrees btdc at 1000 rpms. Everything was fine including the idle. The Manufacturer recommends 1 hour varying rpms up to 2000 rpms. Once I went to stage two which is 1 hour up to 3000 rpms, I hit 2200 on the tach and the engine acted like it was about to die. If I give it more throttle it will kick in and get the engine up to 3000 rpms but in that range the engine runs really bad. I have checked the float level and that is good, I have also checked the accelerator pump and that seems fine(the carburetor was rebuilt last year with another issue and mistake on my part). This only happens under load. Also when I installed the new motor I did remove the outdrive (SX) and aligned the engine, which was way off and I think I got it aligned but it was still a little tight getting the alignment tool in and out plus it was a real pain putting the drive back in. Does anyone have an idea what could be the problem? I think I have tried near everything.....Thanks in advance for any help you can offer.
 

alldodge

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Staff member
Joined
Mar 8, 2009
Messages
42,346
I hope someone can help me, I am about fed up with this boat. I have purchased a new (not Rebuilt) 3.0L Vovlo Penta replacement engine for my 98 Glastron. I completed the first period of break in including setting the base timing to 2 degrees atdc and checked the advance which appears to be around 15 degrees btdc at 1000 rpms. Everything was fine including the idle. The Manufacturer recommends 1 hour varying rpms up to 2000 rpms. Once I went to stage two which is 1 hour up to 3000 rpms, I hit 2200 on the tach and the engine acted like it was about to die. If I give it more throttle it will kick in and get the engine up to 3000 rpms but in that range the engine runs really bad. I have checked the float level and that is good, I have also checked the accelerator pump and that seems fine(the carburetor was rebuilt last year with another issue and mistake on my part). This only happens under load. Also when I installed the new motor I did remove the outdrive (SX) and aligned the engine, which was way off and I think I got it aligned but it was still a little tight getting the alignment tool in and out plus it was a real pain putting the drive back in. Does anyone have an idea what could be the problem? I think I have tried near everything.....Thanks in advance for any help you can offer.

If initial timing is 2? ATDC: 15? BTDC, plus or minus 2?. At 2400-2800 rpm maximum
(total) advance is obtained and should be 26? BTDC (plus or minus 2?).

I don't think timing is the issue, I think your running out of fuel. Check fuel lines, filter, anti-siphon valve and then put a Vacuum/fuel pump gauge on after the fuel pump. Should be 4-7 psi
 
Last edited:

bergadam

Seaman Apprentice
Joined
Mar 27, 2011
Messages
31
AllDodge, you were correct, I had a spacer on my fuel pump that came with the engine kit. I removed it and the engine runs 90% better but I still have a little stumble in that range which leads me to believe now I need to fine tune the carb. I will let you know. Thanks again for your thoughts....
 

bergadam

Seaman Apprentice
Joined
Mar 27, 2011
Messages
31
Just an update to help people out, the new motor required more fuel, I upped my carb jets....problem solved
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,548
I would be checking the alignment again now that you have run it awhile. Don't want to be pulling the engine for a new coupler.
 
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