'87 4.3 mercruiser, replaced waterpump, now no spark

[SCash]

I have a 1987 Sea Ray Seville with a 4.3 liter V6 Mercrusier with a Thunderbolt IV ignition system. My engine has ran very well this year until I overheated last week. I pulled the boat and the next day I dropped the lower unit to check the water pump. Just before I pulled the lower unit (with water supply) I started the engine for a few seconds. It fired right up and I turned off the ignition.

I then dropped the lower unit and found a melted housing on the water pump. I replaced the entire assembly, including impeller. I then (following directions of several sources) placed the throttle and lower unit in forward gear (holding the prop in place to ensure that I didn't slip out of gear) and reattached the lower unit. By turning the prop, I found that I have forward and neutral but no reverse (assuming this because I can turn the prop in both directions with the throttle in reverse). I then attempted the same procedure in neutral and reverse with no luck. I tried to do this probably 20 times and could never get forward, neutral and reverse correctly. So I put the throttle and lower unit in forward gear with the intention to recheck with engine power to see if that made a difference.

I then could not get the engine started. I checked the engine and found nothing melted from the overheating and spark tested it. I got out the volt meter and while I didn't get any readings that were too abnormal, I replaced the coil and ignition sensor and I'm still not getting any spark. I have a generic manual that is telling me to replace the ignition amplifier next but it seems to be testing ok....

So I guess these are my questions, have I gotten something out of whack when I dropped the lower unit that would cause me to lose spark? Is there another area to check? AND, any suggestions on how to get the gears in correct order while reattaching the lower unit? I have tried dozens of times and just can't get it right. Will it somehow kick into reverse with engine power?

Obviously I am a bit of a weekend warrior when it comes to mechanics, any information you could give will be greatly appreciated!

Thanks everyone

 

[Evinrude Boater]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

Take the lower unit off and shift it into forward by rotating the shift rod clockwise while rotating the prop counter clockwise. Make sure the throttle is in full forward too when you reinstall the lower unit.
I'm guessing that your throttle position is messed up with the lower unit not being installed in forward gear and the neutral switch isn't activated when you try to start it.

 

[SCash]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

Ok just to be clear, I can still crank the engine. The lower unit issue would cause a loss of spark only?

And is it counter clockwise while looking at lower unit from the front?

 

[SCash]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

And also just to be clear again, I have tried everything and ever combination to get this thing back on and just can't figure it out. It acts like I am just maybe one notch off, like I'm almost there but I'm not.

I have replaced a few waterpumps in the past so I do feel somewhat comfortable in doing this repair, it just seems as if I'm missing something here.

 

[SCash]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

Ok, I managed to get spark and start the engine (neutral switch). Tomorrow I am taking the lower unit off and trying to get the shift rod lined up properly. I know this is going to be a pain. I have literally tried in forward, reverse and neutral dozens of times. Also have tried with the throttle all the way forward AND with forward barely engaged.

Does anyone have any tips/tricks? I am not doing something correctly and it's a bit frustrating to say the least. Anything in detail would be great. Thanks Evinrude Boater.......

 

[Bondo]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

Ayuh,... Put the controller in forward,...
Wrap a bungee strap around the propshaft, attaching the ends to the anti-cav-plate,...
Load the bungee by turning the propshaft slightly, shift into Forward,+ Install it...
The tension from the bungee will HOLD it in forward...

 

[SCash]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

As a rule, if I'm looking at the back of the boat, forward gear will turn the prop ccw correct?

 

[SCash]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

Oh one more thing, the female end of the shift rod (that is attached to the outdrive on the boat) locks into place when the lower unit is present. When the lower unit is off, it seems to "fall" and can be turned and moved quite a bit. I feel that this may be part of the reason why I keep getting knocked out of gear (this thing only needs a fraction of an inch to be out of gear).

What is the best way to handle this? Should I hold it "in place" with a pair of needle nose pliers or what?

 

[SCash]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

Sorry, one more thing, can I adjust the gears on the shift cable instead of dropping the lower unit again? if so where can i find it?

 

[Bifflefan]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

As a rule, if I'm looking at the back of the boat, forward gear will turn the prop ccw correct?

I think thats Wrong. standing behind the boat the prop should turn CW, or to the right, which ever you prefer. Look at the prop and think like water. when you trun it, it should push the water back.

 

[Evinrude Boater]

Re: '87 4.3 mercruiser, replaced waterpump, now no spark

When you shift into forward you spin the prop ccw when viewed from the back of the boat. Leave it in full WOT position. When the lower gear case is off the boat the shift shoe will be loose, you just have to position it and try to hold it as you reinstall the lower unit.
I don't understand what you mean by adjusting the gears on the shift cable.