V4 1987 Looper Low Compression & Backfire In One Cylinder

[Riley C]

No the crankshaft seal rings are internal parts.----Have seen problems with them.-----Clean that carburetor and test run.----Check carburetor float bowl , they are often warped.

Thanks again,

so take port carb carb off and clean bowl. Do you need to access jet, or can clean without removing? Big help

if the gaskets aren't damaged should I temporarily put them back in. To get it under test again, or wait til I can buy new ones?

I have had such bad luck with this boat, 3k what do I expect I guess.

Thanks guys!

 

[Tassie 1]

Yep,
they are too lol
20 yrs since that bad year,
have wanted to go out for years and salute them as they go past mid way down the Tas east coast,
hasn't happened yet,
something always comes up or it's too dark to see

 

[Riley C]

There will probably nothing open until Thursday at the very least,
local yokels ( Hobart ) aren't back until the 3rd,

Compressor and screwdrivers scrapers etc etc

Acid bath if there's no seals etc
be careful with that if you go that way though, follow the instructions re safety gear kids and other animals etc etc

Thanks Tassie!

yeah I have sprayed a little diluted acid but don't want to go too hard on it.

i have messaged every supplier/wrecker in south east Qld, like a desperate crazy person. As I want to get on the waterf or the break.

Riley

 

[Riley C]

To me it looks like someone was using a generous amount of gasket sealer at one time.

Would that that be the gunk around jacket face?

 

[Riley C]

Whoa. Meant to recommend 50:1. 40:1, as currently used, is on the rich side, and may contribute to issues you describe.

Yeah initially I thought that's all it was. Especially carby wise. The backfire on that one piston has got me beat, to much fuel on float?

 

[racerone]

That backfire is known as a ----" lean sneeze "----It is " outboard speak " for not enough fuel to that one cylinder.------Then funny things happen inside the engine !

 

[Riley C]

That backfire is known as a ----" lean sneeze "----It is " outboard speak " for not enough fuel to that one cylinder.------Then funny things happen inside the engine !

Thanks Race

I was just reading on here about reed valves. Could it be the lower port reed blowing compression and spitting it that carbs throat?

Managing to pickup head gaskets tomorrow, maybe carb kit.

Thanks again!

 

[racerone]

Look at the reed valves when carburetor is off.

 

[Riley C]

Hi guys,

I Have a Carb Kit , Reed Gasket, and head gaskets to pick up tomorrow. Quick question, what am I looking for on the reed valves an do i take the bank off?


It idles fines until the sneeze, but doesn't explain bad compression/. Unless its a gasket yeah?

 

[Faztbullet]

Just make sure you do correct carb as looking at carbs the one's on left feed the port side. That the small bore looper and compression should be 110psi or higher. Lean spit could be from gasket on side of carb leaking or throttle place not fully closing(sync/link)

 

[Riley C]

Just make sure you do correct carb as looking at carbs the one's on left feed the port side. That the small bore looper and compression should be 110psi or higher. Lean spit could be from gasket on side of carb leaking or throttle place not fully closing(sync/link)

Thanks Faz

i had no idea that was the case. So the right lower carb is the issue (when looking at them) would mean it's the starboard lower piston? Does anyone have the numbering for the pistons?

do you know gaskets part number? Or is where the carb body meets the reed box?

going to pull apart today.

 

[Riley C]

Just make sure you do correct carb as looking at carbs the one's on left feed the port side. That the small bore looper and compression should be 110psi or higher. Lean spit could be from gasket on side of carb leaking or throttle place not fully closing(sync/link)

Do yo have a step for sync link? Or do I get from manual? Thanks again.

 

[Tassie 1]

Hi guys,

I Have a Carb Kit , Reed Gasket, and head gaskets to pick up tomorrow. Quick question, what am I looking for on the reed valves an do i take the bank off?

so those frantic phone calls did pay off then lol
who was open xmas day or was it on ebay/ gumtree?

 

[Riley C]

so those frantic phone calls did pay off then lol
who was open xmas day or was it on ebay/ gumtree?

Outboard marine wreckers park ridge! Haha turned out they only had the head gaskets. Not the carby kit for looper, I'll have to order it.

 

[Riley C]

Hi guys so I pulled down the carby and reeds. Found the idle bullet that goes into face of starboard lower carb. It was sitting on the reeds/plate. I'm thinking this was it.

as I definitely took photos before pull down and it wasn't there like there others before I started. Some must have had it previous service. Last owner thought it was spitting a good thing lol.

The reeds had some scum on them. They look like steel ones.

all back together tonight. I'll do a comp rest in the morning, fingers crossed!

thanks for all your help boys.

 

[rothfm]

Just a thought about smoking at start and then clearing up....Normal, they all do. Not a terrible concern as with the lean sneeze.

I have a 140 looper, from start to 30 sec's it smokes, clear up then run fairly smoke free from that point. Very common.

 

[Faztbullet]

Thats the pullover vent jet....only works in the 2500-3500RPM range. Are you testing on a hose????

 

[Riley C]

Lean sneeze is gone!

compression stil only 90psi. I give up on that one.

its most likely the crank seal like Raceone said then.

cheers guys

 

[Riley C]

Thats the pullover vent jet....only works in the 2500-3500RPM range. Are you testing on a hose????

Hahaha bit small for a piece if that's what you're asking?? I found that in the reeds, god know how it got there. Since the work though sneeze is gone.

Cant get the damn compression up though.

 

[racerone]

Reed valves and crankshaft seals have NOTHING to do with compression in the cylinder !