1976 888 Fuel Questions

[ratdude747]

Per my wife, the portion in blue is what was coming out the prop:



The part in red is the muff blowby. Can confirm the blue portion is only present when running.

Hoses are (and were) connected as shown in the diagram. No sings of burning on the exhaust boots either.

 

[dubs283]

Yeah, that's too little water to be present at the exhaust, should see at least some at the idle relief ports as long as there's no blockage prior.

The muffs are allowing a lot of water to flow past the sealing area. Make sure the water intake area the muffs seal around is clear of debris.

The round style have a better fit over the intake and clamp a bit better. The sea water pump on muffs needs a bit of help from the hose water pressure to aid drawing water to itself.

 

[ratdude747]

Yeah, that's too little water to be present at the exhaust, should see at least some at the idle relief ports as long as there's no blockage prior.

The muffs are allowing a lot of water to flow past the sealing area. Make sure the water intake area the muffs seal around is clear of debris.

The round style have a better fit over the intake and clamp a bit better. The sea water pump on muffs needs a bit of help from the hose water pressure to aid drawing water to itself.

The muffs were a gift from a friend. No debris, they just don't seal very well. I had the hose on full blast.

I thought if the impeller neded help from hose pressure that that that meant a bad impeller? Or is such needed to offset the lack of ambient water pressure one would have in a body of water?

Ill see about getting different muffs.

 

[alldodge]

I use the same style muffs and don't have an issue.
My comment comes from the amount of flow, so maybe the tension or adjustment need to be looked at

 

[ratdude747]

I use the same style muffs and don't have an issue.
My comment comes from the amount of flow, so maybe the tension or adjustment need to be looked at

Well, let's give that a try. Smashed the bar down in the vice...



Here's what the results is at full hose:

View attachment VID_20240515_200155.mp4

Splash out is a lot more "vigorous"... It wasn't dripping down the prop like that before (when not running).

That said, running it (no video, my wife was busy gaming), it didn't help, temps climbed to near 175 in a handful of minutes at which point I killed it.



Also, it seems my alternator isn't working... It had been earlier:



The belt is old... But not obviously bad. I didn't hear squealing belts either. I do know that I am getting voltage drop in the harness (currently 12.1v on the GPS speedometer in accessory, 11.2v in run, accessory is only going to said speedometer), but even then, I was getting at least 13v in run before, which is why I mention the belt.

I did hear a clapping noise this last run... I think it was the muffs blowing off pressure? Sounded like it was coming from the muff area. Still a lot of blow by when running.

Safe to say the impeller is suspect and I get to fight the outdrive this weekend? I have the impeller in hand, but need to get a better oil fill pump that doesn't leak all over (had to top off with a squeeze bottle because I lost so much due to pump leakage). Not to mention I had a rough time getting the drive put back in... Most of that was the shift fork, though.

 

[ROY WILLIAMS]

Well, let's give that a try. Smashed the bar down in the vice...

View attachment 398149

Here's what the results is at full hose:

View attachment 398150

Splash out is a lot more "vigorous"... It wasn't dripping down the prop like that before (when not running).

That said, running it (no video, my wife was busy gaming), it didn't help, temps climbed to near 175 in a handful of minutes at which point I killed it.


View attachment 398152
Also, it seems my alternator isn't working... It had been earlier:


View attachment 398151
The belt is old... But not obviously bad. I didn't hear squealing belts either. I do know that I am getting voltage drop in the harness (currently 12.1v on the GPS speedometer in accessory, 11.2v in run, accessory is only going to said speedometer), but even then, I was getting at least 13v in run before, which is why I mention the belt.

I did hear a clapping noise this last run... I think it was the muffs blowing off pressure? Sounded like it was coming from the muff area. Still a lot of blow by when running.

Safe to say the impeller is suspect and I get to fight the outdrive this weekend? I have the impeller in hand, but need to get a better oil fill pump that doesn't leak all over (had to top off with a squeeze bottle because I lost so much due to pump leakage). Not to mention I had a rough time getting the drive put back in... Most of that was the shift fork, though.

the new muffs two water hoses left/right outdrive .....the 140F of the engine ...
damaged it of that one muff hose , damaged it ....175F engine water hotter ...

 

[ratdude747]

FYI: Removed and tore down the alternator... some signs of corrosion in the rectifier and bearings have seen better days. Rebuilding it, as it's a Delco Remy 10si with some marine additions, none of which affect the rebuild parts (other than a jumper on the 2-wire plug, which I can remake if I can't transfer it). I will also be replacing the belt, preferably with a more-modern notched-tooth style V belt.

While I have the belt off, confirmed good rotation on the water pump. Unless the pump impeller has rusted off (which I have seen in the automotive world), probably not an/the issue.

Will plan on getting supplies to change the impeller again. And fetching a better set of muffs.

Note: I stopped my tests at 175 due to that being a convient point on the temp gauge. At least with my trucks it's normal for the temps to go above the thermostat set point on intial warm up, but then cycle above/below it a bit after the thermostat opens up (for example, my 1995 Ford Ranger has a 195 T-stat; it will go all the way to 217-220 before the initial thermostat opening, then cycles between 190 and 205 from then on). Hence why I wasn't stopping right at the 140 the new thermostat is rated for.

 

[alldodge]

Might want to back plush some hoses

When splitting drive see if the tube was not connected correctly

Get a short piece of clear hose 1.25 ID, and a barbed fitting. Remove hose coming from the drive at the thermostat housing and install clear hose. Will see if water is making it to motor

 

[ratdude747]

Outer tube not looking too good. Inner tube still in upper outdrive and looks ok.

Edit: should have bought another housing kit. Housing is melted. So much so the impeller is stuck on the shaft.

 

[alldodge]

Good to find it now

 

[ratdude747]

Game over.

After a 5 hour round trip I made it back with the mercruiser kit... Only to find the shaft and lower housing are also trashed.

Had to do a lot of filling on the shaft die to impeller can material being friction welded to the shaft:


And the lower housing is melted...


The shaft may be OK since I dint really file the seal area. But the kit didn't include the lower housing... And I long threw away the old one.

Will edit it more thoughts...

 

[nola mike]

Dunno if the mc-1s have the same plastic water pocket in the upper as the alphas, but that drive got toasted pretty good, so might want to check that out while you're in there

 

[ratdude747]

Dunno if the mc-1s have the same plastic water pocket in the upper as the alphas, but that drive got toasted pretty good, so might want to check that out while you're in there

Will look. Yes, there is a plastic water pocket upon review of the best exploded views I can find.

In the mean time, I did ebay an NOS OEM lower impeller housing. Wasn't worth today's drive since I'll have to cover up the exposed outdrive areas anyway...

Edit- water pocket looks fine.

 

[dubs283]

The oem sea water pump kit is compatible with two different base assemblies

Your MC-1 drive uses the "tall" base assy

When the MR/Alpha drives were manufactured the difference in bearing/race orientation on the driveshaft required a retainer for the race located directly below the pump. A "short" base assy is required for these drives

The water pocket cover in the picture looks normal

 

[ratdude747]

The oem sea water pump kit is compatible with two different base assemblies

Your MC-1 drive uses the "tall" base assy

When the MR/Alpha drives were manufactured the difference in bearing/race orientation on the driveshaft required a retainer for the race located directly below the pump. A "short" base assy is required for these drives

The water pocket cover in the picture looks normal

Which is what I figured. West Marine doesn't sell the lower piece, so had I talked it all apart first I would have known to stay home and order both online. But, I also wouldn't have made it to North Indy by 5, hence my haste in going up there ASAP. Good story and excuse to get Skyline Chili, even if I did blow 5 hours and $40 in gas.

Lower plate o-ring was no good. Not sure if I messed up or if that was the result of resorting to a slide hammer for removing said plate.

Outdrive oil looked sketchy... Lots of tan junk in it. Not shiny like a bushing went. Moisture? Junk settled in the unit that fresh oil and some muff running knocked loose? When I drained it last time, it had the same look but not as bad.

One final note: it didn't show up in pictures well, but the sierra impeller I ordered is identical to the quicksilver one dimensionally. Hub metal has a different patina, but despite a supposed difference dimensions I read about, the only way I can tell them apart is the sierra one is still sealed in a bag!

 

[ratdude747]

To put a close on the alternator tangent: Rebuild hit a snag, which lead down a rabbit hole that ultimatly has me convinced that it was actually working fine.

As it turns out, the voltage regulator is a custom part. It has an extra stud drilled and epoxied which works with a jumper on the 2-prong connector to turn it into a one-wire alternator. That stud is jumpered to to the output stud, completing the modification.

Plenty of one wire conversion kits exist, some of which are similar. However, with most of these kits (and likely this alternator before I tore it down) have a drawback- by being self-excited (what the 1-wire mod does), it requires "high" RPM to start producing power. Which would explain why it was working when I was running it way too fast... and on a boat isn't an issue due to the nature of boat engine usage and deep cycle batteries. Heck, the 900RPM idle speed I'm currently at (the lowest I can make it, throttle screw all the way stopped) may be enough to self-excite some regulators.

I'll order the/a correct voltage regulator and rebuilt it as said voltage regulator requires. I've already replaced the bearings... they were on the way out and were likely to start failing soon. Not to mention how badly plugged the spark arrestor screens were- I'm sure the internal electronics weren't too happy with that either. Not a completely useless job, just another headache and waiting game due to my ignorance (that's what I get for being a Ford guy who doesn't know GM alternators?)

 

[ratdude747]

Parts came in!

Good news: I was able to rebuild the impeller (blades aren't facing the same way, but I read that will correct itself on first start as long as I get it on muffs and started soon ). After a lot of fighting and cursing (shaft rotation issues) my wife and I were able to get the outdrive back together just in time for storm sirens to go blaring . While waiting the storm out, I was able to get the alternator rebuilt with a correct voltage regulator (that will be a new thread). After the storm passed (thankfully it didn't rain too much), I was able to go out and fill the outdrive (like last time, pumped as much of the 32 oz in as I could, nothing out the vent but the drive supposedly takes only 28 oz???) and install the alternator/belt.

The bad news is the muffs don't seem to fit. Rod hits something in the intake:



Is something wrong with my drive, am I using the muffs wrong, or is this model not actually "compatible with all mercruiser"?

 

[dubs283]

The muffs pictured are the style recommended for bravo drives. They work on some alpha style and other manufacturers drives but in your case the diverter/intake inserts don't allow for the rod to pass through

When I mentioned the round style I meant the clamp style like you have but with the round seal portion. They are smaller and fit more snug to the intake area than the square style which tend to flare out more due to the bullet portion of the gearcase

 

[Dubed]

Parts came in!

Good news: I was able to rebuild the impeller (blades aren't facing the same way, but I read that will correct itself on first start as long as I get it on muffs and started soon ). After a lot of fighting and cursing (shaft rotation issues) my wife and I were able to get the outdrive back together just in time for storm sirens to go blaring . While waiting the storm out, I was able to get the alternator rebuilt with a correct voltage regulator (that will be a new thread). After the storm passed (thankfully it didn't rain too much), I was able to go out and fill the outdrive (like last time, pumped as much of the 32 oz in as I could, nothing out the vent but the drive supposedly takes only 28 oz???) and install the alternator/belt.

The bad news is the muffs don't seem to fit. Rod hits something in the intake:

View attachment 398408

Is something wrong with my drive, am I using the muffs wrong, or is this model not actually "compatible with all mercruiser"?

The instructions for those muffs tell you to drill a 1/8' hole on both sides to allow the wire to pass through

 

[ratdude747]

The instructions for those muffs tell you to drill a 1/8' hole on both sides to allow the wire to pass through

I didn't see any instructions in the package... But if that's a safe move, not a problem.