1993 2200 SR will not run over 3500 rpm at WOT

[Medic3005]

Hey everyone I am new here not sure if I am posting in the right place but I am having some problems with my boat. My family just bought a 1993 2200 SR with a rebuilt 5.7 mercruiser in it and we have taken it out a few times and we have been unable to get it over 3500 rpm at WOT and it will only run about 30-35 mph we at first thought it may be the pro so we changed it from the 21 that was on it to a 19 and still not very much change the engine seems to be running fine but it will not get on plane nor reach the WOT range or speed for the engine. What could the problem be we have already checked the fuel and got rid of all the bad old fuel and changed the fuel water separator and the carb is working fine but we do not know where else to look to fix this problem any help is appreciated. Thanks

[pascavone]

well, lets see:

1. how many people do you have on the boat at the time? try it by yourself, with 1/2 tank of gas.
2. It could just be your throddle cable limit set wrong.
3. use your cell phone GPS to check the speed, and make sure its set to MPH and not NMPH.
4. If your not sputtering, and I would guess Alpha I drive, then I put the old prop back on run some sea trials.
5. I'd go to autozone and buy a $20 tach and hook it up to see if your boat tach is correct.
6. Trim tabs always stay up until your on plane.... they don't work until your on top of thew water, and act like a parking break dragging.
7. put the people in the middle of the boat when going on plane.

[seapuppy]

welcome to the zoo...
if it's not gas related ..then you need to check the tune of the engine...also is the bottom really clean??..that will cause unimaginable drag on the boat...you should be hitting between 4200-4800rpm wot...so...I'd say that the engine needs a serious tuneup if your bottom is clean..and your not totally overloaded...


sP

[shrew]

Agreed with the above. Tuning (in particular carbs), over weight, overpropped can cause this. First, I'd be testing with 2 adults, 1/2 fuel, no gear. Once at WOT, are you trimming the drive out? Make sure you go one click at a time and watch the tach. With each tick out, you should see the RPM's increase. Obviously don't go so far out that you cavitate, or even start to porpoise. No Tabs. Then see where you're at.

The next thing I'd do is remove the carb and have it rebuilt. This is really nothing more than completely disassembling the carb, removing all the gaskets and jets. Soaking it in carb cleaner (the pain can that you submerge the carb parts in for 24 hours. Then remove them and fine tune clean them. Insstalling new jets and new gaskets, then reassembling and reinstalling. Look at fuel filters and make sure those are changed. then repeat the test.

[pascavone]

stick your hand in the water and check to make sure your tabs are full up.

[Medic3005]

The bottom is very clean and has a fresh coat of wax. It is the alpha 1 outdrive. When I had it out I had 4 people on board but most of them moved to the middle and it helped some. I'm going to look into rebuilding the carb and take a closer look at the throttle cable too it seems a little hard to move like it binding some is there a way to grease or lubricate the throttle cable? No trim tabs on my boat and a half tank of fuel very little gear besides the required safety gear.

[ss3964spd]

Med,

The symptom could be caused by all sorts of issues as noted above. Noting that the bottom of the boat is clean and you've tried different props eliminates those as being potential problems.

What carb is on the engine?
What type of ignition system (points, electronic)?
Does the engine run great all the way up to 3500?
When it gets to 3500 and you try to push further, does the engine start to run rough or does it's sound change?
Will the boat get on plane easily?
Can you put the throttle in neutral and rev the engine past 3500 (make sure it's in the water)?
Have you verified that when the throttle lever is at WOT that the carb throttle blades are open all the way (you can do with with the engine off)?
Have you verified that the carb choke is fully open when the engine is at operating temp?

I don't think the problem will be solved with a carb rebuild. By guess is you have an ignition or fuel delivery (to the carb) problem.

Dan

[Medic3005]

I believe the carb is a Rochester quadrajet. It has the thunderbolt ignition not sure if it's points or electronic. The 3500 is with the throttle pushed all the way there isn't any further that it can go. The plates are opening completely with engine off haven't had the chance to test the choke yet. The engine will get up to about 3600 in neutral out of the water with a quick rev but that's about it. The engine doesn't sputter or run rough it just will not get above that rpm. Is it possible that the timing could be off since it is a newly rebuilt engine? Also it will get up on a plane but has a hard time maintaining it with only 4 people on board. Also the throttle is very tight like it is binding the cable sometimes should the cable be replaced it hard to get it to push forward sometimes

[CountryME]

This may sound silly, but have you checked all the plug wires? I had one pop off on my 4.3 and didn't realize it until the performance was off.

-JP

[ss3964spd]

If the engine will not rev past 3500/3600 in neutral then it isn't a carb problem. Well, not an internal carb problem. That engine will easily rev to redline and beyond using only the small primary barrels of the Qjet when the engine is in nuetral.

The Thunderbolt Ig is electronic. Are you saying that ever since the engine was replaced it hasn't rev'd past 3500?

Verify the choke - though I doubt that's the issue.
Try disconnecting the throttle from the carb, start the engine and let it warm up (good time to verify the choke), and manually work the carb (make sure the boat is in the water or you have muffs on the drive). If the engine still won't rev past 3500, and you are confident the tach is correct, either the timing is way off (my bet) or you have a major obstruction somewhere between the gas tank and the carb.

Dan

[Medic3005]

Sorry that was a typo about the revving in neutral it will rev up to redline in neutral. I have access to some portable scales so I'm gonna weigh the boat an trailer tomorrow to rule out it being water logged too. I'm also looking into the fuel pump tomorrow too