Please Look and give thoughts.

[Spillman1979]

WOT only turning 4k RPMS. I have cleaned carbs, new fuel and done a compression check 120 on all 4 cylinders. I changed the prop it is a 13p that's exactly what came on it. It's a 45 hp classic fifty, I have not touched the timing or anythin. I was going to clean my exhaust ports as suggested could this be the problem . 0ne video is idle and the other is WOT. Any ideas ?

 

[flyingscott]

That sounds more like it's running on 2/3 cylinders not 4. I would do a spark test

 

[Spillman1979]

Sparks test has been done, and I have good spark on all 4cyls. I just came in from the garage and removed the lower unit and looked up the exhaust tube and I see no blockage .

 

[flyingscott]

Cylinder drop test

 

[jimmbo]

How long have you had this boat and what is it? When you rebuilt the carbs did you check the sync between them and the ignition system, and verify that the carbs are opening fully?

 

[Spillman1979]

I will try the drop test in few, I was afraid to do this because spark jumping when. the boots are pulled off. I didn't want to hurt anything. This boat is a 17ft tournament V Bass Tracker, and I have owned it 8 yrs it's a 1987 model.

 

[Spillman1979]

Also, this was doing the same thing before I rebuilt the carbs.

 

[Spillman1979]

anything else

 

[Spillman1979]

could it be a switchbox?

 

[jimmbo]

Have you verified the spark can jump a 3/8" gap? It sounds like a dead cylinder

 

[Spillman1979]

you say dead cylnder, do you mean no spark on it? I will check spark again tonight.

 

[flyingscott]

It means you have a cylinder taking the day off do the drop test.

 

[Spillman1979]

As I was on the water yesterday, I shut the engine down and pulled number 1 off and started it up sounded the same, the is shut it down and pulled number 2 and started it still sounded the same then I did number 3 and the same result . and it would not start at all on cylinder 4 alone. any help is qreatly appreciated as I live 2 hours from nearest boat shop for repairs.

 

[flyingscott]

Your motor probably won't run on one cylinder anyway. The correct way to do a drop test is to have it idling and pull each wire one at a time and listen to the change in the idle. Since 4 seems to be a problem spark test and compression test.

 

[Spillman1979]

Ok, will do tonight after work.. I know I have done compression check and had 120psi on all 4cyl. however 5he spark check shows spark but maybe it's not powerful enough I will check again.

 

[mgjtkt]

I know you said you cleaned the carbs But, the carb float bowls are held on by bolts that are also the main jets. Did you look at the main jets with a magnifying glass? Trash has a way of wedging itself into tiny places. Ask me how I know- had them off three times before I found something.

 

[Spillman1979]

I will check your theory this weekend. The bolt your talking about is on the center of the carbs bowl correct, and the jet is in the center and screws out? should I unscrew the jet cause I didn't do this when I cleaned them .

 

[racerone]

I believe the screw that holds the bowl on is just a screw.---Does NOT meter fuel.

 

[Spillman1979]

The bottom bolt on my floats is that just a bolt not the main jet, I'm not sure where the main is.

 

[Spillman1979]

how could I verify fuel to all cylinders?