Boat will not plane

[waybomb]

Hook up a vacuum gage. Post results for both engines at idle. Describe any needle movement.
Disconnect the throttle linkage. Actuate the throttle quickly to wide open and let off just as quick, while intensely watching the vacuum gage. Does it go to zero vacuum? Did it get there smoothly? On the way back to idle, what exactly did the needle do?

What brand engines-Mercruiser, crusader, something else?

Did they time the engines? Are you comfortable with turning the distributor?
What ignition system do you have? Points? Do you have a dwell meter
and know how to use it, and adjust the points?

Vacuum gage can tell us all about the intake and exhaust cycles. W need to adjust the dwell if a points system, and then check timing.

[waybomb]

Let's look at something simple as well.

With the engines and everything turned off, not running.
Go to the bridge and open the throttle all the way.
Go down to the carburetors.
Pull the flame arrestors off.
Manually open the choke and secondary air butterflies
Look down the carburetor - the throttle butterflies should be perfectly vertical.
If not, find the linkage adjusters on the throttle cables at the carburetor, and adjust until the butterflies are 100% open.
Then go to the bridge, close the throttles, go back down and make sure the throttle butterflies are closed, and the carburetor's throttle linkage is up against its stop.


If the throttles were not all the way open and you had to adjust, go take it out for a ride and see how it performs.

[nolacarver]

Thanks for the suggestions Fred, i will try them over the weekend and post the results.

[Ramsport47]

Any update on the performance issue?

[Seif911]

Hmmm...so the point you have your boat at now is similar to mine. It sounds like your starboard engine is good and now you need to fix the port. Why did they not rebuild the port carb? That is what I am planning before my boat hits the water next year, rebuild both carbs. I also have 1 engine at 3200 and 1 at 3600. I might even have the same engines . I also will be epoxing the plugs as Fred suggested. I believe I am leaking through the plugs since it takes a little to start (empty fuel bowl?) but idles perfect.

Good luck and keep us up to date.

[nolacarver]

Just getting back to work on my boat... I did the test suggested by Fred and here is the results. Vacuum test: both read 18 at 700rpm jumps quickly to zero when I manually hit wot then drops quickly to 22 then back to 18. the needle chatters a little at idle. It has electronic ignitions and both engines are crusaders. Ticking noise from port is getting loader and the coolant level was very low, I think I may have a leaking head gasket. not sure how to tell for sure.

[waybomb]

Is the "chattering" quickly between about 17 and 19? That would be worn valve guides. Wouldn;t worry about it too much if that ius what it is. How many hours on the engines, how often is the oil changed, and what oil are you using?

Idel vac is good and you throttle blip indicates a genreally good engine.

Need to find out what the noise is.
Does it seem to be under a valve cover? If so, pull that valve cover and look for a rocker arm when the cam is on the baseline. May be a bad lifter or someting with the rocker / pushrod / valve. Don;t go too long with this condition!