Author Topic: Diagnosing the 3.7L Ignition Issue. (Read 33796 times)

Rich_V174SS · « **Reply #40 on:** July 30, 2016, 10:43:14 PM »

I notated your pic

dorelse · « **Reply #41 on:** July 30, 2016, 10:58:35 PM »

Quote from: Rich_V174SS on July 30, 2016, 10:33:41 PM

I just looked at your pics again and it looks like the yellow/red wire that is taped up is supposed to be going from the slave to the starter, in place of the new yellow wire you added.

Well, of course this started life as the mid-80's 3.7L with the stator, etc, so its had the Alt conversion done on it. So yeah, there's been some hands on the wiring already.

Rich_V174SS · « **Reply #42 on:** July 30, 2016, 11:03:32 PM »

The orange wire is most likely going to the alternator which takes the place of the old regulator. There was a red/purple going to the regulator but that can be taped up and just put aside. But yes it looks like a bunch of changes were made that didn't need to be, probably because a non-solenoid starter was used on the engine so all the battery wires got relocated to the slave solenoid. Make the changes I suggested and take another pic to post here.

dorelse · « **Reply #43 on:** July 30, 2016, 11:07:31 PM »

You're correct Rich, the Orange wire starts life as a Red wire from the alternator, disappears into a taped up section and emerges as an Orange wire and a Red/Purple wire.

Of course none of the pictures I'm seeing show a block mounted slave & the starter solenoid. Is there a reason for 2 solenoids?

dorelse · « **Reply #44 on:** July 30, 2016, 11:11:54 PM »

Rich_V174SS · « **Reply #45 on:** July 30, 2016, 11:23:26 PM »

Further changes:

dorelse · « **Reply #46 on:** July 30, 2016, 11:26:05 PM »

I thought it was odd that that yellow/red wire was taped off...I'll clean it all up tomorrow. Thanks Rich!

Rich_V174SS · « **Reply #47 on:** July 30, 2016, 11:26:33 PM »

The block mounted solenoid is just a redundancy thing most marine engines have these days. The wiring diagram I posted earlier shows the block mounted slave in the middle of the page.

dorelse · « **Reply #48 on:** July 30, 2016, 11:39:49 PM »

Yep, checked the diagram you posted...the 2 yellow/red wires were throwing me being that mine are taped off. So I was trying to figure out the alternator conversion and all the other work.

Thanks again Rich, I get what I need to do and hope to post video of it running tomorrow.

Now, I just need the 4 barrel intake & carb parts to show up on ebay. I'll do a compression test again soon and see what the numbers say and if its improved at all.

dorelse · « **Reply #49 on:** July 31, 2016, 01:04:17 PM »

Ok, cleaned up the wiring. Hopefully Rich approved now! The proper connectors were even already on the wires. I think what happened is that with the non-solenoid starter that was on there, someone taped those off as they wouldn't be needed.

Running video to follow!

dorelse · « **Reply #50 on:** July 31, 2016, 01:09:12 PM »

Starts up and WAS running good until 00:31...that, ladies and gentlemen is the sound of a 3.7L throwing its stator magnets off...(whew...I thought the motor had imploded!)

http://youtu.be/eC44g-Qxmyc

dorelse · « **Reply #51 on:** July 31, 2016, 01:22:45 PM »

After figuring out that the motor was ok, I ran it again and it purrs very nicely. I either don't have a working oil pressure sender, gauge, or oil pump??? (hope not). I'd like a working engine temp too...though maybe the cold water is keeping that low...not sure.

Anyway, seems to start up, idle and run great.

At some point, now that its warmed up and running again, I'll do a compression check and see where we're at...thanks guys for all the help getting this motor picked up and helping getting it running!

Now to start looking for the 4-Barrel intake parts to get the HP up to the 190 I'm looking for!

http://youtu.be/oODFyn_Ht6Y

Rich_V174SS · « **Reply #52 on:** July 31, 2016, 02:08:53 PM »

The wiring looks correct now! That engine actually sounds pretty damn good! I'm surprised since the alternator conversion was added that the old stator wasn't removed. I hope the loss of a magnet doesn't affect the harmonic balancer. When I added the alternator to mine I pulled the stator and regulator off and just left the cooling pipe that was attached to the back of the regulator.

If compressions are low the engine will be running at a reduced horse power so with the addition of a 4 barrel I doubt it will see 190hp. It might knock it back up to 160-170.

On your first video right at 30 seconds when you bumped the throttle it sounded like something changed in the engine, like it started gurgling before the magnet got chomped. I guess that was the exhaust pipe falling off. ;-)

Rich_V174SS · « **Reply #53 on:** July 31, 2016, 02:32:20 PM »

If there was no oil pressure it might not run as well as it does because it has hydraulic valve lifters. I would bet the pressure sender is bad, I've replaced a few including my own. The temperature sender is under the front of the exhaust manifold and so is the thermostat. Perhaps it's running cold due to a stuck or missing thermostat if the temp sender is good. Test how hot the manifold gets after it's running a while, it should be quite warm when at temp. The thermostat is a special design that has a "foot" on it that closes the bypass port as the thermostat opens, maybe the wrong one is installed.

dorelse · « **Reply #54 on:** July 31, 2016, 02:45:45 PM »

Yeah, its now vibrating slightly since one magnet is now missing. Can I take all that off without pulling the motor apart?

I think the motor sounds pretty strong and idles down nicely. However, I can't run it anymore since the el'cheapo starter from ebay is now hanging on the flywheel and kept the engine running when I turned the key off. (That's somewhat scary!)

Yep, the exhaust vibrated loose right about then Rich.

I'm not expecting this motor to go in the boat before getting it rebuilt. You know that the 4-Barrel intake for this engine is pricey, so I just need to scope out the parts and look for a decent price. That way I'll have everything when its rebuilt.

Rich_V174SS · « **Reply #55 on:** July 31, 2016, 02:55:06 PM »

Yeah, there a single bolt that holds on the crank pulley, then use a gear puller to remove the pulley. Then just a matter of 4 screws I think to remove the stator.

The new starter toasted? Hung up solenoid?

I 'might' have an extra 4 barrel intake. We'll have to see what kind persuading will be required for me to relinquish it. ;-)

dorelse · « **Reply #56 on:** July 31, 2016, 03:01:01 PM »

Ha, ha Rich... Yeah, I'll be in touch

I'm assuming a hung up solenoid, as soon as the battery is connected (even with the key off) the starter goes...

Here's what's left of the magnet:

Rich_V174SS · « **Reply #57 on:** July 31, 2016, 03:06:25 PM »

Make sure the yellow start wire lug isn't touching the battery cable lug terminal.

Here's a 4 bbl intake on ebay:

http://www.ebay.com/itm/Mercruiser-Intake-485-488-190-170-185-/252431408167?hash=item3ac6159c27:g:q9kAAOSwc1FXZ1eO&vxp=mtr

dorelse · « **Reply #58 on:** July 31, 2016, 03:09:42 PM »

doesn't that look a bit suspect with all the crud on the right? I've seen them with the carb for that price and in better shape.

Rich_V174SS · « **Reply #59 on:** July 31, 2016, 03:20:05 PM »

Probably just some dried up coolant from the cylinder head. Clean off the old gasket and it should be fine. The front cooling hose needs to be changed with the intake and throttle cable anchor point relocated to the top of the valve cover. Optional oil cooler hoses and filter adapter can be added.