Power & Speed

[Aalapuna]

I have a 99 Tige 2100V that is sluggish out of the hole and tops out at 36-37mph (3700rpm). What would cause this?

[spharis]

Is this recent? If it is, it could be a number of fuel delivery issues/tune up issues. Are you carbed or fuel injection?

[spharis]

You sent me a PM that you are carbed, so here are a few things to check. I am assuming you have a Holley 4160, which is about 95% of GM blocks:

• Change your fuel/water seperator.
• Check all the linkage and make sure it is opening the throttle correctly.
• Make sure the choke is opening fully after the key is on for a few minutes.
• Pull your plugs and check the coloring and for fouling.
• Pull the distributor cap off and make sure everything under there looks good, might as well replace the cap and rotor.
• Pull the carb bowl off and check for trash and check the float to make sure it is ok.
• Clean up the X-fer tubes that come out when you remove the bowl.
• Clean the metering block out.
• Unscrew the jets from the metering block and clean them out.
• While you have the bowl off, inspect the accelerator....it is green in color usually. Make sure it isn't dry or cracked.

If you get it cleaned up (you will probably be suprised at the amount of trash in the metering block and/or transfer tubes) and still seem to be having high RPM fuel problems, have a pretty good idea that it is fuel related, you can check/replace thee following:

• Secondary diaphargm. It is a 15 minute or less change.
• Power Valve.....you need to do vacuum test to check, but it can show those symptoms.
• Fuel Pump.....easy to do if you can find a proper replacement. It is probably a mechanical cam driven type. Follow the fuel line from the carb down.

[zad0030]

the prop

[Aalapuna]

has four blade 13/13 now. What would you recommend?

[zad0030]

It could also be any of the things spharis said but the prop will make a huge difference, you could have one that gives you a great hole shot but slow top end or just the opposite.

If you are interested in possibly getting a new one, call ACME, I dont have the number but I know someone on here will. You tell them your boat, engine, transmission, and if you run ballast and how much, and they will give you the prop to suit your needs.

[spharis]

Topping out at 3700 RPM isn't a prop problem. Your max RPM should be 4500-5000. You are having some kind of restriction on the engine. Your carb probably just needs to be cleaned up or your distro needs cleaning/changing. The jets may be clogged which is why you are only experiencing the issue on acceleration and high RPM.

[Graham Morris]

Topping out at 3700 RPM isn't a prop problem. Your max RPM should be 4500-5000. You are having some kind of restriction on the engine. Your carb probably just needs to be cleaned up or your distro needs cleaning/changing. The jets may be clogged which is why you are only experiencing the issue on acceleration and high RPM.

It can be if is grossly over propped , but more likely carby, timing problem plus prop as well

graham

[dogbert]

I have a 99 Tige 2100V that is sluggish out of the hole and tops out at 36-37mph (3700rpm). What would cause this?

Is this boat heavily weighted?

[Aalapuna]

nothing to add extra weight - specs have it @ 3450lbs. checked the engine last night and it's a Mercruiser 350 MAG MPI...could be the injectors?

[spharis]

yes, but more likely a clogged fuel filter. I would start with the basic maintenance items. Ditro cap and rotor, filter, plugs, etc.

[dogbert]

I have the same boat as you, except mines an MPI, not carbed. At 400 hours, my dealer recommended new plugs and wires. Wires don't last as long on a boat because of the higher RPMS you're usually pushing and they wear out after a while.

spharis recommended a lot of other stuff, but I'd start with the simple things he said: distributor cap, rotor, clean the flame arrestor, fuel filter before I'd get too heavy into the other things. We broke 600 hours a couple of weeks ago and my boat's running like a top. Also, I just had to replace the fuel pressure regulator. The shop manager said that the Mercruiser has a diaphram that wears out after 7-8 years. I noticed it because my boat went into alarm mode. It's a nightmare to fix because you have to remove the muffler to get the plastic cover off of the fuel cooler (driver's side). It's probably a dealer item. When they fixed mine, the service tech accidentally pinched one of the o-rings on the fuel intake to the fuel cooler and I had gas spewing into the bilge. Not good. My dealer made it right, so we're all good now.

BTW, there's a site where you can look up your engine's S/N to find out what you have and what parts you need.

[spharis]

spharis recommended a lot of other stuff

My list went out the window when he posted it was a MPI.....

[chpthril]

The thing that pops to my mind is a restricted exhaust due to the age of the boat and the fact that we have low speed and low RPM's.

[dogbert]

My list went out the window when he posted it was a MPI.....

Not entirely, I just prioritized the key items from your list for mine based on my experiences with the exact same boat