Another Big Twin Observation....

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Bill McNamara
Posts: 203
Joined: Wed Mar 11, 2015 8:52 am
Location: Ontario Canada

Another Big Twin Observation....

Postby Bill McNamara » Wed Aug 08, 2018 2:57 pm

My wife and I took our Twin Javelins out to a local benefit Poker Run over the weekend, they ran beautifully.
While doing a post run clean-up today, I noticed that one engine had produced about twice as much unburned fuel during the 2 hr variable speed run. The larger volume was also more turbid and different color as shown in the pic.
I quickly checked the HS needle just now on the port motor, and it seems reasonable at 1/4 turn out.

Some facts:
-First run of the season, so had done a little carb dialing to individual engines (other one shut down during tweaking) in-water, on the way out to the start for both High & Low speeds.
-Both engines had fresh gas/oil mix. (Shell Nautilus oil)
-The boat made 25mph WOT (non GPS) and felt good and sounded better!.
- We don't have a lot of run-time on this rig, as I just re-launched it last season after extensive preservation efforts.
- Haven't got my compression gauge with me, but both plugs look decent.
- I have little digital tach's on both engines, but their info. is all over the place and not useful at this time.

Before I delve any further into the situation, I thought I would share my findings, and see if any you guys had any ideas?


Bill.
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FrankR
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Location: Florida

Re: Another Big Twin Observation....

Postby FrankR » Wed Aug 08, 2018 4:11 pm

So you are catching the crankcase puddle drainage? Offhand, I am wondering why is it black? As for the full one, has it got water mixed in it? Very interesting.

Chris_P
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Location: Hamilton ON
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Re: Another Big Twin Observation....

Postby Chris_P » Wed Aug 08, 2018 4:17 pm

Bill,

Do they run off the same tank or separate tanks?

After a run, pull the plugs....any water droplets on them?

fleetwin
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Location: Rhode Island

Re: Another Big Twin Observation....

Postby fleetwin » Wed Aug 08, 2018 4:22 pm

This sounds like the sort of thing you could chase around forever....Do both engines have similar needle valve settings? There is no thermostats, so engine temp isn't an issue. You state that both engines run great. I guess I would try giving the rig a nice long high speed run, then shut off both engines and tilt them up, maybe at a beach somewhere, to see if there is any drool. If not, then I'm thinking it is a low speed/overboard drain issue. Some engines just do this, while others don't...
I'm assuming you have made sure this is not a leaky gear lube situation.
What are the plastic jugs with the tubes seen in your picture?
Sorry, just don't want to see you rip these beautiful engines apart chasing down this situation....

Chris_P
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Location: Hamilton ON
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Re: Another Big Twin Observation....

Postby Chris_P » Wed Aug 08, 2018 7:23 pm

Don he has an waste oil recovery system set up. That is crankcase fuel/oil mix which is normally dumped into the exhaust cavity.

Bill McNamara
Posts: 203
Joined: Wed Mar 11, 2015 8:52 am
Location: Ontario Canada

Re: Another Big Twin Observation....

Postby Bill McNamara » Wed Aug 08, 2018 9:31 pm

To Frank; Yes I'm catching from the crankcase drain cover.
I thought about possibility water getting into the fuel in the engine, but have no idea
how or why? It's been sitting there for almost 3 days and doesn't seem to have settled
The smaller sample isn't really black, more of a condensed dark blue like the oil.

To Chris; The engines are fed from separate tanks of fresh gas.
I'm planning another outing Friday afternoon, so will re-check HS under load again
and pull the plugs right after a good hot run.

To Don; Not planning a tear down at this point, and appreciate your compliments.
The plastic bottles are as Chris has mentioned, and show the recovered unburned
fuel mix scavanged from the block drain for each motor over the 2 hr run.

I did check the compression after supper, and measure 125-130 top & bottom.
I think the first step should be to get some more hours on these engines, and see if "stuff"
levels out a bit between them.Maybe add some Seafoam???
I didn't open up these two crankcases when I went over them, because they both had good numbers, and they seemed to have had very little use before I got hold of 'em.

Thanks for the input Guys, much appreciated.

Bill.

FrankR
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Location: Florida

Re: Another Big Twin Observation....

Postby FrankR » Wed Aug 08, 2018 9:51 pm

I'm worried about the possibility of water. Did you inspect the exhaust cover inner baffle plate?

Chris_P
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Re: Another Big Twin Observation....

Postby Chris_P » Wed Aug 08, 2018 10:26 pm

Bill,

I too fear your Port side motor is getting water into the powerhead.

That explains the extra volume, as well as the lightened colour.

As Frank stated, first pull the exhaust cover and inspect. I would then try the head gasket. Could also be the lower crank seal.

bobw
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Re: Another Big Twin Observation....

Postby bobw » Wed Aug 08, 2018 10:38 pm

Almost has to be ingesting water to have that much more volume. Strange that although discolored, the port motor doesn't have the usual chocolate/vanilla milkshake color that a high water content normally produces (remember the '69 Fastwin Mumbles posted a few weeks ago?).
Anyway, need to check the usual water intrusion suspects as noted by others.
Bob
AOMCI Member

1954 Johnson CD-11
1958 Johnson QD-19
1972 Evinrude 25202

BillW
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Location: Cape Cod MA

Re: Another Big Twin Observation....

Postby BillW » Thu Aug 09, 2018 5:51 am

Sometimes when a mixture of fuel and water sits, it does stratify but the color doesn't come completely out of the water. I feel like that's what you've got there on the bottom. Colored water. And from the crank case. Uggh. I'd personally be going right after the lower crank seal, as a starting point, with no time to waste. I'd hate to see you loose a crank, or worse, on those beauties.....Even if that's not the cause of the water intrusion, it would be money and time well spent. The seal is probably original equipment; and just because they seem to have low hours, it doesn't mean the rubber is in good shape. JMHO.


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