powerpack problem on my V8??

[hammer250v8]

my boat will only rev to 6000rpm no matter how small of a prop i try! could my powerpack be malfunctioning? it say's in the repair manual that my rev limiter is 6700rpm's and i'm falling short by 700. the motor runs strong up to 6000 then just sit's there.any of you ever have this problem?Dhadley: what do you think? thanks...james<br /> oh, yea...its a 1991 250 V8...

 

[hammer250v8]

Re: powerpack problem on my V8??

bump

 

[Dhadley]

Re: powerpack problem on my V8??

Look at all the numbers on the pack and let us know what they are.

 

[hammer250v8]

Re: powerpack problem on my V8??

ok, i pulled the powerpack off and these were the numbers i found: CD8AL/67 584034 28 B Q OA<br /> hope you can figure these out..thanks..james

 

[hammer250v8]

Re: powerpack problem on my V8??

 

[Dhadley]

Re: powerpack problem on my V8??

That should be the 6700 pack. Have you tried another tach? Changing 2" of pitch should certianly make a difference in rpm. <br /><br />By any chance are you running those Land and Sea dual plug heads?

 

[hammer250v8]

Re: powerpack problem on my V8??

this is a brand new teleflex sportsman tach set on 6 pulse. single plug head's. my top plug on bolth head's is always darker then the rest. do you think the top two carbs need to be leaned out?this is driving me nut's! ive gone from a 23 pitch to a 17 pitch prop and stay at 6000 rpm. i think the motor isn't turning any faster because it sounds the same at the top for all props. could the powerpack be faulty? i know most electronics work or don't work. maybe it could be slowly going bad?i wish i could afford a promax x and stop tinkering and start really boating. another thought; think my coils could be weak at the top end?

 

[Dhadley]

Re: powerpack problem on my V8??

I think I would still double check it aginst a shop tach or an E/J tach. I've seen some aftermarket tachs off a long way. I think you may be right, its an electrical problem but start with the very basic stuff. This is one of those areas that I personally would stick with and E/J product only. <br /><br />Look up under the flywheel and check the 6 outer magnets to make sure they are still in tight and evenly spaced. <br /><br />You may be getting weak spark on the top 2 cylinders but I wouldnt lean them out unless someone has rejetted them way rich.<br /><br />Let me know when you get the tach verified.

 

[hammer250v8]

Re: powerpack problem on my V8??

sounds good!<br /> i'll try to go to my local E/J dealer and rent his shop tach for a run or two. i'll varify the magnets and see if i can have the coil's checked if i can't test them myself.if all fails i'm going to send my powerpack to Raypair to have it rebuilt without the rev limiter. this really sucks! i went from 68 mph with the 25 to 55 with the 17! it's weird; when i was in key largo in february i had the 25 spinning at 6100 in light chop and with 2 passangers. now i turn 5500 with 1 passanger. james

 

[hammer250v8]

Re: powerpack problem on my V8??

i think this problem has to be it's running too fat on all cylinders.the plug's are black around the threads and also the electrode. the center of the plug isDark brown on most and black on two. i remember the guy i bought the boat off of put the boysen reeds in and fiddled with the high speed mixture. he said it could be leaned out more but was afraid to do it. i know how critical it is to have the mixture right on my jet ski(a little off on the top end makes a huge diffrance)i assume it's the same on an outboard!what do ya think?

 

[Dhadley]

Re: powerpack problem on my V8??

I would be very cautious of that. Putting in Boyesens usually means a slight adjustment on the idle circuit, if any at all. About the only reason to fool with hi speed jets in that motor (at stock rpm's) would be if he was trying to run with the airbox cover off or running high test fuel.<br /><br />When rejetting remember this is a two stroke, not a four stroke. So use caution when going by plug color alone. And I dont care what the engineers say - the mid range jet effects the motor throughout the entire range. <br /><br />If the motor used to turn more rpm with the same jets and now it doesnt (at the same altitude), something is wrong besides jetting.<br /><br />Good luck!

 

[hammer250v8]

Re: powerpack problem on my V8??

my compression is 150 psi. when he had the boysens installed he also had the head's decked. would that make a diffrance on the high get? i guess i'm going to have to bite the bullett and bring it to a good hi performance mechanic!

 

[Dhadley]

Re: powerpack problem on my V8??

At 150 he probably put a set of small bore heads on. If he cut them too then you need to test and dial it in. At 150 you should be using hi test fuel.<br /><br />Keep in mind that if it once turned the rpm at the same altitude, then its not the jetting.

 

[hammer250v8]

Re: powerpack problem on my V8??

i always run 93 or better fuel. what do you mean by test and dial it in? the fuel mixture? he told me he had the head's shaved. when i once saw 6100 it was on a(blackwater sound, Key Largo) into the wind with light chop. i've never seen 6700rpm

 

[Dhadley]

Re: powerpack problem on my V8??

What spark plugs are you running? What timing at 6000?

 

[hammer250v8]

Re: powerpack problem on my V8??

i'm running champions the oem manual recommends. i have no idea what the timing is, i've never checked it. i changed my spark plug wires and plug's about two hours ago(had a bad wire so changed them all)and the plug's don't look fouled at all now. how hard is it to check the timing on this motor? i know how to do it on a car. is it similar and do i need any special tools?

 

[Dhadley]

Re: powerpack problem on my V8??

The best way is with a test prop but you can do it on the trailer backed down the ramp. You want it in gear and as close to 6000 as you can get it. There is a way to set it initially (as described here many times) but you still want to check it at whatever your top rpm is.<br /><br />Time it off of 1 and 2. The manual will describe in detail how to center the timing pointer and then just check her under a load for the proper lead time.<br /><br />It would still help to know what plugs youre running. We run QL77JC4's.

 

[hammer250v8]

Re: powerpack problem on my V8??

i checked, ql77jc4 are the plug's i run. i'll get the tool to stop my piston then center the timing mark and check the timing. maybe it's eay off?