New Boater Prop Troubles!

[Isthatso]

I think there should be a spacer b4 you put the frt prop on. You can google v/p 280dp and 290dp dou prop diagram. I think the order is.
Spacer, frt prop, locking ring, lock nut, spacer, back prop, spacer, plastic washer, cone nut, bolt. I think you need to install the prop correctly then see how it runs.

If rpms are still down find out why. Your compression #'s seem all over the place. You might try the test again after the engine is warmed up. Make sure each cylinder hits the same # of times with the throttle open. If the comp #s are accurate wide open rpms will be down.

So warm up the engine, pull the plugs and test compression on each cylinder as before.

Count the amount of times that each cyl hits.

Are you saying that my compression readings at the minute are likely the issue I’m having with my power restrictions?

 

[Scott06]

It’s a 434A.

Shall I open a new thread? I have some questions about the compression values I got.

Test was done cold, haven’t tried the old oil down the hatch method to increase psi.

1- 140
2- 107.5
3- 155
4 - 151
5 - 165
6 - 170

107 is essentially a dead cylinder. You don't put oil down the hatch you put it in spark plug hole it will help rings seal if they are shot. Check that valves are closing in cylinder 2

 

[Isthatso]

107 is essentially a dead cylinder. You don't put oil down the hatch you put it in spark plug hole it will help rings seal if they are shot. Check that valves are closing in cylinder 2

Sorry by down the hatch I implied in the spark plug hole.

I will note. When I pulled plugs this cyl had incorrect plug, completely different thread length and hex size to others. Could this cause a coke buildup on the valve perhaps?

I’ve ordered a new set of plugs.

I will fire it up tomorrow, warm her up and take readings again.

Appreciate the help guys; new to the scene so have to bare with me

 

[72fj40]

So warm up the engine, pull the plugs and test compression on each cylinder as before.

Count the amount of times that each cyl hits.

Are you saying that my compression readings at the minute are likely the issue I’m having with my power restrictions?

Yes, let the cylinder hit maybe 4 or 5 times. Each cyldr needs to hit the same # of times to be consistent. As Scott06 said, after your initial comp tests you can squirt oil into a cylder then test again. Squirt oil into the cylder being tested, not all of them. If comp significantly rises it usually means rings if it doesn't rise much then it most likely the top end. If the numbers are pretty consistent and relatively high I'd probably not do an wet test.

 

[QBhoy]

It’s a 434A.

Shall I open a new thread? I have some questions about the compression values I got.

Test was done cold, haven’t tried the old oil down the hatch method to increase psi.

1- 140
2- 107.5
3- 155
4 - 151
5 - 165
6 - 170

I think you should likely do a warm test. Just in case you have a sticking valve on that number 2. But I’d also say that 170 psi is a little high too. Maybe the oil doing that.
Ok. So if it’s a 434a. It’s less hp than the one I had. You’re about 180ish hp with that engine.

 

[Isthatso]

I think you should likely do a warm test. Just in case you have a sticking valve on that number 2. But I’d also say that 170 psi is a little high too. Maybe the oil doing that.
Ok. So if it’s a 434a. It’s less hp than the one I had. You’re about 180ish hp with that engine.

I’ll do a warm test now.

Just to add. Timing was out by a huge margin.

Was about an inch past the actual measurement plate to the retarded side.

Could this be the issue I’ve been searching for regarding my top end power loss?

My manual says that timing should be 0deg at idle speed I believe.

There’s a strange message underneath I can’t make odds of, it’s attached.

Since setting the timing to the manufacturer spec I’ve noticed a tapping noise from one of the cylinders.

I’ll pull rocker cover off and check clearances