Throwing in the towel

[CobiaXL]

Re: Throwing in the towel

Possible voodoo curse placed upon you or the boat?

Im leaning that way,No wonder the boat was so cheap...

 

[Don S]

Re: Throwing in the towel

I would sure send that alternator out to be checked. It is connected to the same electrical system as the ignition.

 

[CobiaXL]

Re: Throwing in the towel

I would sure send that alternator out to be checked. It is connected to the same electrical system as the ignition.

alt wires goes straight to battery.And its a 1 wire that replaced a 3 wire.Ill take to local parts store for a test....Just never know at this point.

 

[infideltarget]

Re: Throwing in the towel

Not to sound remedial, but I am guessing you have replaced the obvious stuff like cap and button, right? I only ask becuase after bringing my '86 GT out of storage and cleaning it up, my wife and I headed into town to eat. Any time I tried to past half throttle, it popped back thru the intake. Fearing the worst (jumped time), I fiddled with the dist, wires, timing light, etc...only to find out it had a bit of moisture under the cap from when I washed the engine. Dried it out, cleaned the crud from the tabs in the cap, and we are leaving rubber in 3rd gear again. Stupid simple crap. One more note...I noticed your block and head are not the same year. I was rebuilding a '80 VW Cabrio with a 1.6L 4 cyl. I was told by a VW race guru that the 1.8L heads worked great on the 1.6L blocks. I did a bit of research (not enough) and decidedto go with it. Everything prepped by the appropriate folks, and assembled by me. All went together perfectly. It had the exact same problem yours is having. Anything over about 1800rpm, it would pop thru the FI box. This is bad, as those FI boxes are very fragile, and do not like backfires. Two solid weeks of late nights tearing it back apart, and rechecking everything I could find. All looked right. Finally broke down, admitted defeat, and took it to a specialist I know. 10 minutes later, he found the problem. The cam drive gear on the 1.8L head was 1/16th of an inch larger in diameter than the 1.6L gear, and had a slightly different tooth count. Just enough to keep the valves from crashing, but off enough to not time. Just a thought.

 

[CobiaXL]

Re: Throwing in the towel

Not to sound remedial, but I am guessing you have replaced the obvious stuff like cap and button, right? I only ask becuase after bringing my '86 GT out of storage and cleaning it up, my wife and I headed into town to eat. Any time I tried to past half throttle, it popped back thru the intake. Fearing the worst (jumped time), I fiddled with the dist, wires, timing light, etc...only to find out it had a bit of moisture under the cap from when I washed the engine. Dried it out, cleaned the crud from the tabs in the cap, and we are leaving rubber in 3rd gear again. Stupid simple crap. One more note...I noticed your block and head are not the same year. I was rebuilding a '80 VW Cabrio with a 1.6L 4 cyl. I was told by a VW race guru that the 1.8L heads worked great on the 1.6L blocks. I did a bit of research (not enough) and decidedto go with it. Everything prepped by the appropriate folks, and assembled by me. All went together perfectly. It had the exact same problem yours is having. Anything over about 1800rpm, it would pop thru the FI box. This is bad, as those FI boxes are very fragile, and do not like backfires. Two solid weeks of late nights tearing it back apart, and rechecking everything I could find. All looked right. Finally broke down, admitted defeat, and took it to a specialist I know. 10 minutes later, he found the problem. The cam drive gear on the 1.8L head was 1/16th of an inch larger in diameter than the 1.6L gear, and had a slightly different tooth count. Just enough to keep the valves from crashing, but off enough to not time. Just a thought.

Yep all wires,plugs,rotor and caps have replaced numerous times.No change....cam and crank gears are exact matches..I made sure when I tore apart the engine and got ready for assembly.

 

[Don S]

Re: Throwing in the towel

Did you by some chance adjust the valves on both engines?

 

[CobiaXL]

Re: Throwing in the towel

Did you by some chance adjust the valves on both engines?

Maybe marine engine is differ but I slowly tighten down rocker nuts till i can't ROLL push rods anymore then back it off a hair.

 

[CobiaXL]

Re: Throwing in the towel

I feel like a idiot,maybe wont know till I can get out on water morrow afternoon...BUT when I was first diagnosing issue,I took the boat for a ride running the fuel line from exterior gas can,I removed the entire fuel pick up from tank to inspect and just stuck the entire fuel pick tube in the gas can.Well after further inspection today,I noticed its a 2 piece...Piece of aluminum tubing threaded into a elbow....Guess what,I put vacuum gauge on the elbow to the end of pick up and vacuum dropped pretty quick.I doped her up real good and tightened it up and presto...vacuum holds.I'M doing the voodoo dance as I type and pricking needles in my eye balls.JK but I really don't know why this wouldn't solve my issue.I'll know tomorrow and post results.

 

[CobiaXL]

Re: Throwing in the towel

This could also explain why the 12v electric pump seemed to lessen the popping,compared to the mechanical pump.Im not even telling the admiral what I found,as I've cried wolf way to many times with this issue and said "its finally fixed hunny"Got to the point where I would get the answer"Really think this is it?"

 

[infideltarget]

Re: Throwing in the towel

Like I said...stupid simple crap. Fingers are crossed! Hope this gets it bro!

 

[Don S]

Re: Throwing in the towel

Maybe marine engine is differ but I slowly tighten down rocker nuts till i can't ROLL push rods anymore then back it off a hair.

That's not even close to how you adjust valves on a Chevy engine, car or boat. No wonder it pops at high rpms.

You go to zero lash then TIGHTEN an additional 3/4 or 1 turn (check your manual).

 

[Don S]

Re: Throwing in the towel

Here is the specs for an 85 Mercruiser 3.0L engine. Same exact engine and specs as OMC.

One note, and this is where a lot of people screw it up, when you turn the rocker nut down to find zero lash, and the lifter stops. That's it, do not start wiggling the pushrod again. Set zero one time and one time only then adjust the additional 1 turn.

 

[CobiaXL]

Re: Throwing in the towel

That's not even close to how you adjust valves on a Chevy engine, car or boat. No wonder it pops at high rpms.

You go to zero lash then TIGHTEN an additional 3/4 or 1 turn (check your manual).

Thats how i do it...I roll rod till zero lash then go 1 full turn tighter...Not sure what I was thinking when I said backing off hair.Maybe the joy of finding the vacuum leak in fuel delivery.

 

[CobiaXL]

Re: Throwing in the towel

Like I said...stupid simple crap. Fingers are crossed! Hope this gets it bro!

Thanks,I hope too.....But not getting hopes up,Ive been in this BOAT before.

 

[infideltarget]

Re: Throwing in the towel

Thanks,I hope too.....But not getting hopes up,Ive been in this BOAT before.

Yuk, Yuk!

 

[Joshua Nichols]

Re: Throwing in the towel

I must say this thread has me on the edge... Now go make a test run...

Funny how we wish hopes and boats went together.. They don't.. With that said.. Hope you got it this time...

 

[CobiaXL]

Re: Throwing in the towel

Test is complete,same old song and dance...No change....Ahh maybe a little.I got another issue that probably wont fix my issues but it needs addressed now,Tearing off the exhaust/intake manifold,I finally got some carb cleaner up and under the intake,what a tight spot but it revs up when sprayed...In between #2 and #3 cylinder has to be leaking or its cracked.Let me your remind you that this is the 2nd intake.First one had same pop issues.Head has been surfaced but not manifold,so while its off I will surface it.

 

[infideltarget]

Re: Throwing in the towel

Test is complete,same old song and dance...No change....Ahh maybe a little.I got another issue that probably wont fix my issues but it needs addressed now,Tearing off the exhaust/intake manifold,I finally got some carb cleaner up and under the intake,what a tight spot but it revs up when sprayed...In between #2 and #3 cylinder has to be leaking or its cracked.Let me your remind you that this is the 2nd intake.First one had same pop issues.Head has been surfaced but not manifold,so while its off I will surface it.

That may very well fix your issues! In those threads I posted for you there were several folks that had lean pop issues due to vacuum leaks. I even mentioned that very issue back in post #38, about your intake manifold sealing surface. By jove...I think he's got it! Get some really good gaskets this time too.

 

[CobiaXL]

Re: Throwing in the towel

Or Im told its this....My ports don't exactly line up with intake to head but was told it would work fine by a omc guy.Well after talking to michganmarine they recommend this and they say thats causing vaccum leak.

http://www.iboats.com/Adapter-Plate-Kit-Mallory/dm/view_id.711092

 

[CobiaXL]

Re: Throwing in the towel

My head hurts........Picked a great week to stop smoking.