91 celebrity first splash, issues??

[voodoochikin]

Ok so I finally got the boat in the water. 1991 celebrity 200.. 21ft, 5.7l, stainless 19x14.5" prop.. At full throttle I'm only getting 4,100rpms and a max of GPS 45mph when trimmed out. Also can't trim up all the way or it cavitates. It feels like its not revving out all the way. But when checking throttle plates, they are opening fully. Also the vacuum secondaries are opening under load. After being shut off for 5 minutes...it took forever to get it started again. I'm not sure where to start here.

 

[MikDee]

Okay, most boats will cavitate if you trim out all the way, you have to come back down a little so the prop grabs, and find the "Sweet Spot". You might be having a fuel starvation issue, if it's hard starting after running, then being shut off for a little while. With the engine off,Take off the flame arrestor when this happens, and pump the throttle once to see if it's squirting gas into the carb, or not? It could be hot flooding instead as well? By doing this it may help you confirm which way to go.

 

[voodoochikin]

I did that and it appears the accelerator pump is working. I've cleaned and regasketed many many qjets over the years. This one is clean. Doesn't seem gummed up. I guess iI need to check the idle air screws. Also I'm idling at like 400-500rpms. Not good in a car. But I'm new to inboards.

 

[tpenfield]

A bit more background information about the boat would be helpful . . . is the boat new to you, any major work done on the boat or engine?

RPM's are a bit low, but not terribly so.

Also is your trim limit set to the spec's ? it is only supposed to go up a certain amount, as measured at the trim rams. As stated, often, you cannot go up to the full trim range under power, as the prop begins to ventilate (not cavitate)

 

[voodoochikin]

New to me. No major work. Previous owner had throttle cable replaced. Carb rebuilt (possibly the problem). Water pump replaced. New bellows. Trim limits appear to be correct. I've just never had an inboard so I wasn't sure if I should be able to trim up to limit.

 

[MikDee]

I'd say check your idle screws, and also it seems like all else is okay, so next I'd check the timing. That might be the only thing giving you hard starting, and holding the rpm's back? You probably have a Merc. EST electronic ignition, and must put it in base mode to set your timing. Usually no special tools needed, just a certain procedure to follow.

 

[voodoochikin]

Not sure what est ignition is without looking it up but my phone service is garbage up here... Can't load Google but I boats loads good...and that's what counts!! Lol. I know its thunderbolt ignition which seems to be pretty desirable amongst the masses.. The distributor doesn't appear to have been messed with. The paint is intact on the clamp bolt head and no indication its been moved ever. I don't feel like this boat is water logged as the boat and trailer are 4,100lbs according to my locsk truck scale. Which seems to be about right. I'm gonna have to pick up a service manual. Any particular one that's recommended?

 

[MikDee]

You probably have the Thunderbolt IV ignition, I think the T-bolt V came out later. There are service manuals online right here, under the "Mercruiser section" at the very top where it says "Adults only" and "Info for DYI's", just click on that, and choose from the menu what you need.

 

[MikDee]

Here's some good info for you:
http://www.boatfix.com/merc/Techbk/95/95HGB4.PDF

 

[bruceb58]

I'd say check your idle screws,

Idle screws do absolutely nothing at full throttle or off idle for that matter.

 

[voodoochikin]

true....but my idle is low and I don't wanna be a tool and go cranking up the idle screw without first checking the idle air circuit.

 

[voodoochikin]

Also, Im worried ill screw something up trying to figure out why its not reaching full WOT rpm range. Probably end up taking it in somewhere.

 

[UNSUREBOATGUY]

No expert here, but is it possible that the tach in inaccurate?

 

[voodoochikin]

I suppose its possible. But why am I only hitting 45mph on glassy water. Shouldn't this boat be faster?

 

[voodoochikin]

I have a spare tach I'll hook up

 

[MikDee]

Did you check your timing like I mentioned?

 

[voodoochikin]

Not yet. I need to wait on my friend as he has all the equip I need. I'm guessing the timing degrees on the engine cover are good to follow?

 

[voodoochikin]

Here is a video of the first full throttle run... after a bit I cut the throttle back. But we were hitting 4,100-200 rpms and 45mph on the gps.

 

[MikDee]

Nothing there?

 

[voodoochikin]

it shows a video attached... weird. heres the link

https://www.youtube.com/watch?v=M_2fYPWrA5s