1976 888 Fuel Questions

[ratdude747]

Got it to idle a bit better:

• Tightned the carb nuts with a 1/4" ratchet instead of a nut driver.
• Discovered I had a loose connection at the engine wiring harness plug (causing me to lose all 12V power after idling a bit)

Still has a bad vacuum leak. In addition to the PCV issues, I'm pretty sure my carb/carb spacer gaskets are wrong. used the same soft paper/foam type eBay gaskets (4 bore) on both sides of the spacer. Might be wrong.

Will edit in some pics.

 

[ratdude747]

A few more notes based on research I'm doing:

• Per several youtube and eBay references (along with parts lists confirming the use of a breather oil cap with steel wool media), the 888 is in fact a stock PCV setup (never ran vent tubes the flame arrestor). But, I have yet to find a parts list that calls out what the PCV valve was supposed to be. If nothing else, since I'm strictly freshwater, I might just grab the generic automotive 302 PCV and call it a day.
• The carb spacer is a custom modded part... that vacuum port was drilled and tapped by somebody (and any more, Edelbrock 8711 is currently a plastic part!).
• I think I might be able to nuke the spacer entirely. The intake (an Edelbrock performer 289) has several threaded vacuum ports that I could put a barbed fitting into and run my hose with such. But I don't think the throttle lever will clear the water hoses on top of the intake. Edit- Nah, the spacer with a port is correct. The similar (stock 4 barrel) Mercruiser 233 (5.7L) had a PCV barb at the carb base... this setup is meant to simulate it. Just need to replace the air chuck with a proper barb, the cobbled line with something proper (high pressure automotive fuel hose ok?), and the PCV with something appropriate.
• Edit2- Since the carb was factory tuned for the later Mercury 5.0 that didn't use PCV, I'm reading that I may need bigger primary jets. Currently I have .057 jets (factory is supposedly 0.58, but whatever). I also have a 6.5 power valve installed but I have an 8.5 that was an option in the carb kit. Either of these options suggested? Edit3- Nah... supposedly the idle screws are enough, unless the 888's 351 cam is different from the later 5.0 and has more lift/duration? Edit4- Nah, if anything they're the same more or less.
  
  

Edit4- Probably a mix of the PCV and moron here not having the idle tuned right. It wasn't idling great but it was idling until the power cut (due to the loose connector). I also noticed that barely moving the throttle resulted in engine racing (tried to go to 3000RPM, I pulled back immediately!)... probably way too lean, if not a vacuum leak?

 

[alldodge]

PCV is a PCV so long as it fits

 

[dubs283]

Probably best to do a compression test

If all is good, check/set dwell (if applicable) and timing, then use a vacuum guage to set idle speed and air mixture

 

[ratdude747]

Doing some more reading... Apparently this carb and intake combo is trouble.

EdsCarburetorForum-4100 with a Edelbrock 289 performer intake

Can I use a 4100 on an Edelbrock performer 289 intake. This intake looks like a cast iron Ford, but is aluminum. I would have to use the factory space

www.tapatalk.com

At a minimum I'll want stouter gaskets. These thin ones are moving despite being locked down. The old spacer to intake gasket was 1/8 or 3/16 and rigid... What I bought is 1/16 and floppy.

Would explain why I was hearing a massive vacuum leak and why it was acting like one as well (give it any throttle and its off to the races!).

Sigh...

 

[ratdude747]

PCV is a PCV so long as it fits

Fair enough.

Took the PCV apart:

• Looks like the big hose (Marked "Motorcraft 5-55") and it's PCV valve (an aluminum Motorcraft EV8, Made in USA ) are in fact stock. The hose isn't in that bad of shape for 48 years old... some mild internal cracking on the very ends (past the spring clips) but the working area is crack and rot free. The PCV valve is still moving nice, and moving a lot nicer after rinsing it with some carb cleaner. Call me cheap, but I'll reuse both of these (although I may swap the hose for a molded replacement, some of my old ford truck suppliers make such things). The hose and PCV nipple are 1/2"
• The other hose is just automotive fuel line. Where it curves it hits the intake... and the cardboard they had as an insulator is there because the hose was actually burnt to a crisp! Didn't have any obvious through-cracks, but not a good part at all. I can do better!
• The carb spacer is tapped for 1/4NPT... not sure if that's something edelbrock made as a custom part or if somebody else did it (if they did, it looks well machined).

New plan: ($40 shipped on Summit racing)

1. To fix the carb spacer to intake sealing issue, I found a fel-pro marine gasket that should fit the bill (17847)... Holley 4150/4160 bolt pattern, 1/4" thick, open center (which I read is good- allows some crossover). With some photo editing, here's what that gasket will roughly look like
   
   Should fill the gap nicely. Closer to/better than what was there originally (I think it was 1/8, thicker than what I currently have!
   
   
2. To fix the PCV issue, it's easy. Spin the spacer 180° and install a proper barb (such as this one I ordered). Might need to trim the hose due the 4 barrel being longer than the original 2 barrel, but I think that'll work a lot better than having the extra loop that burns up...

https://www.degreesymbol.net/​

 

[ratdude747]

Got some work done yesterday and some headway today.

First, tried to install the new parts. Had to get longer carb studs (and even with the new ones, they're still too short to thread into the intake all the way ). And found out that rather than tapping the PCV port, they shoved the fitting in:



While I was out of town the afternoon, I got said studs and a 1/4 NPT tap. Now, we're talking:








New fuel line:



Due to it getting late, I opted to try starting it today... To no avail. Per some things I read elsewhere, pulled the carb (fuel coming out vent tubes still looking very yellow, must be me), and found the base gasket screws had settled a bit. I also opened the secondaries a bit per some likely bad advice. Still nothing.

As a last-minute idea, I raised the idle speed. Now, it runs, but is stuck at 1700-2000RPM even with me backing the screw way off while running:

View attachment VID_20240505_095102.mp4

At least the tach says that's 1700. Sound right???

I suspect part of my problem is that I'm used to automotive carbs with fast idle cams. I'm not used to guessing where to set the throttle when starting.

I did shut it down after that video was taken... Ran maybe 3 minutes in that state. After. The manifolds and all water hoses were hot. Temp gauge reading 140, right at where the thermostat that should be in is rated for.

This afternoon I'll pull the carb and back the secondaries back to the original position. See what that does for me.

Getting closer?

 

[ratdude747]

Backed off the secondaries. Seems to be behaving now.

Might have an overheating condition. Let it run for a few at 1100rpm, then smelled burning rubber and shut down. Light smoke near front right bank, but my fuel line wasn't over there wasn't burnt. Maybe some old whatever burning off?

After that, I was able to idle it...

View attachment VID_20240505_133352.mp4

During the 1100 run my wife reports that some water was coming out the prop... About the amount one flows a faucet in the winter to prevent pipe freeze. Impeller is new and I had it on muffs.

160 seems a bit hot? I'm kinda scared to run it much lest I burn the riser boots...

I'll check timing in a bit once it's had a moment to cool off.

 

[alldodge]

Running the motor above 1500 can and usually does burn the impeller. A garden hose cannot supply enough flow so impeller runs dry enough to burn

 

[ratdude747]

Running the motor above 1500 can and usually does burn the impeller. A garden hose cannot supply enough flow so impeller runs dry enough to burn

Great. I had the hose on full blast at least. Guess I get to pop the outdrive off again? See below.

In the meantime, I did find the timing was way off. Set it to the 10 btdc that I've read and had been paint marked on the indicator. Even at lowest idle, it runs 1000.

But, the temps climbed higher... Shutting down for the time being.



Probably smoked a new impeller then?

 

[alldodge]

But, the temps climbed higher... Shutting down for the time being.

Probably smoked a new impeller then?

Would be my guess

 

[ratdude747]

Would be my guess

Confirmed... Still having water sloshing out of the muffs at 1000 yet goes from 100 to 200 in a handful of minutes.

On a side note, the gas that came out may not have been bad. My lawn tractor seems to not mind it at least.

 

[ratdude747]

Question: since I started messing with this boat back in September, it never flowed water well if at all. I did get it to stumble and kinda run at 1100 RPM back then and while I didn't run it much, water never made it out the prop despite making it to the block and manifolds. This is what prompted replacing the impeller, which was soft but intact upon removal.

Wonder if something is plugged up. Riser issue? The right manifold was full of rust when I had the end cap off while helicoiling said manifold.

 

[cyclops222]

Sadly it is a old poorly maintained motor before you bought it.

 

[ratdude747]

Doing more research. Seems that there are additional water exits besides the prop hub. And I haven't seen any water come from them.

Seems the same pre-alpha water drain reference pic is used on several threads (on iBoats) from 14 years ago... but sadly was a photobucket pic that's long been deleted/paywalled. Would these holes being plugged with junk/bug nests/etc. cause this?

I'm pretty sure the outdrive is turning. During my final test run, I did try to put it in gear and it did react.

It's a good possibility the impeller is toast. However, I'm suspecting more is at play here.

Edit- looks like all water on the 888 does come out the exhaust:



Also reading that my use of silicone paste as impeller lube may have been a bad call... dunno. Guess I get to redo the impeller again and see.

 

[dubs283]

You can test the exhaust cooling passages for flow with a garden hose attached at various points and following the flow indicated in the diagram with arrows. If little or no flow there's most Iikely a blockage somewhere, if good flow there may be an issue with water supply from the impeller or blockage prior to the t stat housing. I would recommend only using oem sea water pump replacement parts for your drive

Baby duck dish soap works best for impeller installation. Provides good lubrication for proper install and bubble evidence for proper operation upon inital test

 

[ratdude747]

You can test the exhaust cooling passages for flow with a garden hose attached at various points and following the flow indicated in the diagram with arrows. If little or no flow there's most Iikely a blockage somewhere, if good flow there may be an issue with water supply from the impeller or blockage prior to the t stat housing. I would recommend only using oem sea water pump replacement parts for your drive

Baby duck dish soap works best for impeller installation. Provides good lubrication for proper install and bubble evidence for proper operation upon inital test

What I was going to ask about. Will try.

 

[ratdude747]

Finally had the time (and weather) to do some more work.
Hose tested the risers... other than the hose/riser combo acting like a plumbing trap (which makes sense, duh), flowed fine.

Per my wife, the starboard riser is discharging as one would expect (most flow out of starboard gimbal bypass, with some also out of the prop and port bypass), but for whatever reason, the port side hardly discharges out the prop (most came out the port gimbal bypass, with some out the starboard bypass, and a small amount out the prop). This an issue?

Also indirectly checked the manifolds... all of that is flowing nicely as well.
Noticed that the T-stat had been RTVd (with the clear stuff no less )... popped that open, found that a gasket was also used and the T-stat installed is a 160 degree aftermarket unit (automotive???).

So, I've ordered a new impeller (not the kit, since I recently did the full kit and it has hardly run since then) and t-stat kit (new gasket, 140 degree t-stat), both are Sierra (Pretty sure the impeller kit I used last time was also Sierra, I've read that they sometimes are a slightly different size than OEM and mixing can be an issue).

 

[ratdude747]

Installed the thermostat today. Dealing with old Shellac (not a gasket ) was "fun"...

Anyway, I retested... 10 minutes later, I hit 175 on the gauge and killed the test.

Here's the water flow at 900-1000rpm:

View attachment Messenger_creation_32f76a5b-1d08-419e-8876-c99c4f2dcae3.mp4

That water by the prop was confirmed by my wife (who shot the video) to be all coming out the prop. Is that the right amount? Or is that too little, confirming a bad impeller?

 

[alldodge]

So far as I can see it's not coming out of the prop. Looks more like it's escaping past the muffs. Show some pics while running at the muffs

The thermostat housing on the 888 has it's own issue and why it was changed many times