1982 150hp blackmax powerhead swap issues

[rjcamel2355]

Hey folks,

I picked up a used powerhead to swap onto my midsection, checked compression and spark 120PSI on all 6, spark on all 6. Got the motor onto my midsection, and bolted on. Swapped known good carbs, and powerpacks onto the engine. Put it onto the hose, fired it up sat there and idled perfectly, revved it up just a little bit, and it revved up like it should.

Took it to the lake yesterday and it ran like absolute dogshit:
1. Wouldn't idle well (I figured it would need adjusted) so I attempted adjusting it, but made no difference.
2. After I got it to where it would stay running, tried to take off, never would plane, would hit around 3000RPMS, with the carbs wide open.
3. The entire time there was a LOT of white smoke that smelled like raw unburned fuel (I just premixed 6 gallons, 50:1 in a brand new tank, so I know there was oil in the fuel, at idle it was blue smoke as normal.
4. No fuel film on the water (gas rainbow effect)
5. Took the carbs apart, and cleaned them, even though I knew they were clean, but it made absolutely no difference.

So, aggravated and disappointed I went home, and I pull the flywheel off (just the top part, not the big nut) I marked it, and pulled the stator off, and swapped the stator thinking that it may have possibly been my issue. Set the flywheel back in the same spot (unless my mark moved on me...permanent marker). Tried to start the engine back up and it pops, bangs, and everything but never tries to start. I think I got the flywheel one bolt hole off......

I'm lost here, I've never had one of these blackmax engines be such a headache. The exhaust ports on the donor motor, matched up perfectly to the mid section, and were the same as the motor that came off of it. Good seal around the powerhead base, no water leaks, no fuel leaks. I put a new impeller in it:

Reused:
1. Fuel Pump
2. Carburetors
3. Power packs
4. Stator (now)

The reason the motor was swapped is the water pump failed, caused it to overheat and the piston came apart in number 2 and 6.

Any help here would be awesome... I'm almost certain it's a timing issue..... that was there before I bought the motor..... but I wanted to ask the experts here.....

 

[Chris1956]

White smoke is steam. See if your spark plugs are steam-cleaned. If so, you are getting water into the cylinders.

If that is not it, Set the #1 piston to TDC with a screwdriver. Check the timing mark. If you are off 1 hole, the timing will be off 60*, which is easily observable.

A link and synch is in order to assure the carbs are synched with the spark advance. Make sure to set the max spark advance properly.

 

[rjcamel2355]

Spark plugs were covered in fuel/oil when I pulled them after seeing the white smoke.
I'll put #1 @ TDC today and see where the mark lines up on the flywheel.
Is there a procedure to link and synch the carbs with the spark advance?

I did remove the idle stabilizer box..... because all the wires were coming apart, and I didn't want that to become an issue....
I've been looking for the correct setting for the timing @ cranking, and Max advance..... could you give me any information on that?

I've never had such an issue swapping a powerhead with a motor like this.

 

[Chris1956]

I would expect idle pickup timing to be 0-9* ATDC, and max spark advance to be 21* BTDC. Do you know how to set those?

 

[Chris1956]

I suppose white smoke could also be steam from overheat. You might check that.

 

[rjcamel2355]

I've been reading on how to set the timing, but please correct me if I am wrong:
1. Pull all plugs except #1, and ground them.
2. Find .462 with a dial indicator
3. Once .462 is found, make sure pointer is set to 0*
4. Crank engine with the timing stop not touching the block (Where it would sit if there was no throttle given, and at idle) this shows the Idle pickup timing, the 0-9* ATDC Correct?
5. Crank the engine with the timing linkage all the way to the stop this shows the max spark advance (The idle stabilizer is removed, should it still be set to 21*?)
Should start and idle on the hose about 850RPMS, and roughly 750RPMS in the water (adjust the idle stop to achieve the rpms the motor/I like)

Please do tell me if I am wrong there.

No overheat alarms, water pressure was about 5PSI when I could get it to idle, and when I got it to "take off" water pressure was roughly 15-18PSI @3000RPMS give or take a little. Heads were cool to the touch at first, but it never got so hot I couldn't hold my hand on them. When I pulled the plugs at the lake during the water test they were all wet with fuel/oil sort of blackish, wiped them off, and tested spark at the ramp and all 6 were sparking, tested compression also: 120PSI on all 6.

This was prior to me coming home and pulling the flywheel to swap the stator, and as I mentioned it now just pops and bangs and sputters, I definitely don't want to blow the exhaust tuner out or blow out/break the reeds so I didn't try to keep starting it. It's very likely when I put the flywheel back on I was a bolt hole off where I had marked it. It's the type of flywheel that has the big nut in the center, some 1/2nuts surrounding it, pull those and the plate, and the flywheel comes off then you can get to the stator via the 4 allen/hex screws. It didn't start the popping/banging stuff until I pulled the flywheel and swapped the stator.... however i know the stator is good so it has to be and error on me putting it back on that's causing that issue.

 

[rjcamel2355]

Will a dial indicator like this: https://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html from harbor freight work for finding the .462?

 

[Chris1956]

I would think the Dial Indicator you cited will work. Set the motor to TDC, zero the pointer and then set the piston until the dial indicator reads .464 inches. Now adjust the timing pointer to indicate the .464 on the timing decal. Of course the outer flywheel needs to be set correctly, but that should be obvious, when you set the #1 piston to TDC.

On your step 3, you want to set the throttle until the carbs are just about to open, but still closed. This is idle pickup timing, and should be 0-9*ATDC. I would aim for about 4.5* ATDC. The rest of your timing procedure looks OK.

best of luck....

 

[jimmbo]

Just out of curiosity, what year was the donor powerhead from?

 

[rjcamel2355]

Jim, I was told an 82. Serial number on mid says 82. I cannot find a place on the block that says what year it is.

I don't have the dial indicator yet, but I will get it tomorrow. I put the flywheel at 0* or what I believe is 0* (flywheel says 0) and I am adding a link to the photos of the powerhead and of the screwdriver in piston and the indicator mark.

http://imgur.com/a/j5ZgL

 

[rjcamel2355]

Whoa! Checked the flywheel today. Turned the key to see if it would fire and bang! Shot a flame out by the prop. I'm not a expert marine guy like you folks. But I've been arms deep in small blocks since I was 16. That's a sure fire sign of being out of time. Am I correct?

Correct me if I am wrong, but the flywheel turning charges the stator, stator sends voltage to the powerpack. Then the triggers tell what cylinder when to fire correct? More less? I know the stator is in the right position. Flywheel seems to be lined up in the same spot I marked it. Is it possible I didn't notice the backfire when the boat was in the water due to the exhaust being under water? And the white smoke I saw was fuel like I thought? Or am I just completely wrong here

 

[jimmbo]

Engine can backfire for many reasons, unburnt fuel in the midsection and gearcase will ignite if a spark occurs in a cylinder when the exhaust ports are uncovered. Sometimes it seems just hot exhaust gas will do it too. You need to verify if all wires from the stator are going to the correct terminals on the switchboxes and that the plug wires are going to the right plugs. Plus as already mentioned you have to verify the timing on cylinder #1

The original engine was what year? The cowl looks like 86 - 89

 

[rjcamel2355]

I would have to look at the title for the original engine tomorrow. But you may be right it may be a mid 80s. I'll verify the stator to switch box wires tomorrow, I know the wires from the switchboxes to the coils and the plug wires are correct I checked those this afternoon.

I'll get the dial indicator and timing light tomorrow and check the timing. It looks to me like the linkages on the throttle cam have been messed with at sometime. But it could just be me.

 

[Dukedog]

tha power head in your pics is '87 at least if heads and other parts are original... might be a serial number stamped on tha welsh plug on top of tha motor... there will be a "build date" in 1/8" numbers (m/d/yr.) stamped at tha base of number two cyl. on block half.. kinda right behind tha bend in tha timin' arm....

send me an email addy and i'll send ya a coupla pdf manuals... won't be motor specific but justa 'bout all v6's set up same as for as timing, link and sync goes.....

max timin' on yours around 20* is safe.... idle is what ever you like with motor in tha water, in gear.. idle timin' is tha only thing adjusted to determine idle speed/rpm...

jan.. get tha spark plug adapter for tha dial indicator.. makes life a lot easier.

back fire/flames of any kind is gonna be timin' and/or wiring screwed up in one form or another.....

 

[Dukedog]

jus noticed one other thing 'bout tha motor... there is a hose with a bolt in it on top.. that hose didn't come about till mid/late '89.. you need to change tha fitting that your water pressure hose is connected to to a "t" to accommodate that hose AND tha smaller water pressure hose..

 

[rjcamel2355]

No serial number on the plug. It's just a black plug. First place I looked, however there is a date stamped on the side of the block 12 8 96 if I remember correctly.

I'm headed to the tool store today for a light and a dial indicator. I'll try to find the spark plug adapter also.

Is it possible since the stator isn't for that year powerhead that it could be causing the backfiring and such. Since it only started that after I changed it? Even though the stator was working perfectly before the water pump went out on the other powerhead or am I just overthinking this?

Pm sent with my email address dukedog, thank you, and everyone else assisting me with this issue.

 

[rjcamel2355]

So it needs to have that hose, and the water pressure gauge hooked up.... I wondered about that. The poppet housing cover on the other block had that piece broke off. So I just stuck the bolt in this one thinking it would be okay...

 

[Dukedog]

that hose was added when tha 40 amp water cooled rec/regulator came out but was also added to all production motors even tha 16's like yours.. that thing has been tweaked on some.. noticed idle timin'/stablizer and regulator is missin' but no big deal.. most shuck those anyway... never seen tha stator actually cause a backfire..... its NEVER a good idea ta separate tha flywheel/hub assembly....

 

[rjcamel2355]

I pulled the idle stabilizer off. The engine didn't have a regulator on it but the original powerhead did.......yeah I regret separating the flywheel now especially since it obviously didn't fix anything and just made it worse.

 

[444]

Did you do a proper link and sync? My black max looked good, I bought it as a "good running/driving boat" and ran great on the muffs but it wouldn't do more than 1500rpm on the water. I pulled the carbs, cleaned them and still no dice. A proper link and sync and after that it ran and drove perfect.