Couldn't get skiiers up after changing props... plug gap?

[H20Rat]

Re: Couldn't get skiiers up after changing props... plug gap?

i'm still curious how an I/O was hydrolocked and apparently nothing broke? That is a 1 in a million chance, it just doesn't happen, EVER. Even just using the starter to turn it over is more than enough to damage pistons/rods/bearings.

 

[Silvertip]

Re: Couldn't get skiiers up after changing props... plug gap?

You also mentioned some strange plug gaps. .1 is reaaaaalyy wide. .03 is 30 thousanths. In other words, .1 is three times as wide as .030.

 

[sschefer]

Re: Couldn't get skiiers up after changing props... plug gap?

Hmmm, I used the word Vortec because the mechanic referred to it as that. Can you tell from this pic?

http://web.me.com/mark_armstrong/Site/Last_Import.html#20

Its a 1998 5.7L Mercruiser V8 with a 2 barrel carb.

I looked at the Pic's and it's not a Vortec. It's a standard GM Marine 5.7l motor. The good news is that it's pretty easy to work on these. These are built with almost the same torque specs as a truck engine then given a cam that works better in 3500-4500 rpm range. They put stainless steel valves in them to fight corrosion, water cooled exhaust and a closed loop cooling system with a raw water heat exchanger. Nice setup and if taken care of they'll last a long time.

Now tell us how it got hydro locked, meaning, how did you fill a cylinder up with water? I almost willing to bet that you misunderstood the word hydrolock for vaporlock.

 

[RIDEPATE]

Re: Couldn't get skiiers up after changing props... plug gap?

i'm still curious how an I/O was hydrolocked and apparently nothing broke? That is a 1 in a million chance, it just doesn't happen, EVER. Even just using the starter to turn it over is more than enough to damage pistons/rods/bearings.

There are many more hydos in his future loking at the height of the exhaust outlets. Maybe they have internal flaps?? I doubt it. I'd put some exterior rubber flaps on it before I ran it again. Even then it will sketchy.

 

[sschefer]

Re: Couldn't get skiiers up after changing props... plug gap?

There are many more hydos in his future loking at the height of the exhaust outlets. Maybe they have internal flaps?? I doubt it. I'd put some exterior rubber flaps on it before I ran it again. Even then it will sketchy.

Nothing wrong with the setup, it's all factory stock.

 

[RIDEPATE]

Re: Couldn't get skiiers up after changing props... plug gap?

Nothing wrong with the setup, it's all factory stock.

Just because it's "Factory-Stock" don't mean it's right. They look way too low to me, and probably the reason it hydro'd in the first place. Maybe it does have internal flaps and they are stuck/broken.

 

[sschefer]

Re: Couldn't get skiiers up after changing props... plug gap?

Just because it's "Factory-Stock" don't mean it's right. They look way too low to me, and probably the reason it hydro'd in the first place. Maybe it does have internal flaps and they are stuck/broken.

Possibly hung. I still think it was vapor lock. None the less damaging except you're filling a cylinder with fuel instead of water.

 

[mancho]

Re: Couldn't get skiiers up after changing props... plug gap?

granted, I might be using the incorrect terminology.

Heres the facts

There was no existing flapper internal or external. I just had made a slow turn after a tuber fell off or something and killed it. my mistake.

the very low (read SMALL wake) went into the exhaust right after I killed it but i noticed the engine stumble or something like it couldnt shut off... I didn't smell gas and I dont' think it was running rich.

So, attempt to start it, it started to turn over and then nothing, it might of made a half turn maybe not even that. so i try again, nothing, starter is hitting wheel and no engine is truning over. battery was good. I keep trying and eventually broke off 3 teeth on the gear wheel, and not in a row, but every other one.

So after pulling the plugs and finding the water on ALL port plugs, AND noticeable water ejected after turning engine with starter, I got them as dry as possible and them flogged them.

I didn't want this to turn into a engine repair, because as noted, it's kinda riding several categories.

I will check compression, mechanic says he will lake test it. He asked after I indicated this loss of HP, that if there was a big difference between having a skier and not, and I said I didn't think so.

Whats the difference between vapor and hydro? I guess I'll be searching!!

 

[mancho]

Re: Couldn't get skiiers up after changing props... plug gap?

OK, sorry, yes, if you look at that link I put in the initial post you'll see my thread of that experience of the full water in cylinders. how much, it was enough to be really concerned and the reason why the starter couldn't turn the engine.

No, this wouldn't be a stock set up, these pipes are WAYYY low (to avoid the linkage in the steering)... So to avoid the possibility I bought new tips. NOW, I have BOTH internal AND external flappers on it and I just don't kill it until I'm sitting practically still. This is essentially all I can do... I don't see poppin the hood and draining manifolds or to that extent... but I should do the test as I read here in the forum. thats perhaps later this summer.

the flappers are ok, the sound isn't that bad or anything but i just happened to peek over while the engine was running while on the water... they are completely submerged!!!!

 

[mancho]

Re: Couldn't get skiiers up after changing props... plug gap?

OK, so if this is vapor lock: Vapor lock occurs when the vapor pressure of the fuel is higher than the surrounding environment.

Then, I'm pretty sure it's Hydrolock... water significant enough in the engine to prevent the starter from allowing it to turn in normal fashion.

 

[smokeonthewater]

Re: Couldn't get skiiers up after changing props... plug gap?

it is not vapor lock....

DO A COMPRESSION TEST that will tell you if the engine was damaged by the hydro lock.... I suspect that it wasn't... then gap the plugs and put them back in..... Next swap the prop back and try again.... maybe you swapped on a junk prop or a prop with a spun hub....

Report back with your findings....


BTW If I had a boat with thru hull exhaust BELOW the water line I would yank it so fast it would make your head spin... I'd go back to thru prop exhaust and glass the holes over.... having it pass through the hull below the water line is just asking for water leaks and a rotten transom IMHO

 

[mancho]

Re: Couldn't get skiiers up after changing props... plug gap?

Aight, so went last weekend, and I got the stern side gapped correctly, and guess what, we got the first skier up. I'm having a feeling here...

SO I popped my 200+ lb a** in the water and boom, a newbie to my boat pulled me up. INteresting!

While its too windy for me this weekend to go out on the lake (40+ mph gusts in Dallas) I did put 'er on muffs tonight and brought her up at idle to find the NON gaped side, the PORT, the exhaust water temp is LOW, almost cool, and the RIGHT SIDE that I gapped, is HOT ... like 125+

sooooo, I'm just going out on a limb here, but improper gapped plugs can cause all sorts of issues and it's a bigger concern than most give it.

Why would port side be so cold? Is there something about the 1998 GM mercruiser 5.7 L is special about a particular side being cooler?

I know muffs isn't a full lake load run, but I have a sneaky suspicion that my loss of HP is due to the fact that my plugs were at factory gap of WAY TOO BIG.

THanks for all the opinions and thoughts ! much appreciated!