220 Merc. Laser can't plane out

[Jamesone]

I have a 1987 220 Laser that will not take off with a conventional style prop attached. If I put a chopper prop on it, I can get it to plane out, but it takes a little bit. Once I get onto plane with the chopper prop, the boat will pull hard and run well (speedo says 65mph). I have tried different pitch props, and checked compression, fuel pressure, injectors (injected model),etc. The motor does seem to smoke a lot at lower revs, but my mechanic says it is very difficult for a motor to over-oil. He has checked all of the ignition, and helped me check the compression, but has given up. I am going to try to premix some fuel to make sure that it is not adding to much oil, but if that does not work, I will need other ideas to look for and check. Any help or advise would be appreciated.

 

[andy6374]

Re: 220 Merc. Laser can't plane out

Have you checked your spark plugs? Do you have spark on all cylinders?<br /><br />-andy

 

[PuddleJumper]

Re: 220 Merc. Laser can't plane out

What rpm are you running @WOT?<br />Approx how many seconds is hole shot?<br />Does the engine sound abnormal on take off or is it just a long holes shot?<br />Trying to figure out whether it's an engine problem or simply over propped.

 

[PuddleJumper]

Re: 220 Merc. Laser can't plane out

Oh yeah, is your engine trimmed all the way down at take off?

 

[mphsmaestro]

Re: 220 Merc. Laser can't plane out

Jameson, I run a '94 Laser with modified 200 Merc and have great hole shot. No one has asked how deep your prop is in the water. Sounds like you need to raise engine. I run 2 1/2" below transom. You don't say what picth prop. R's at WOT? I run 26" big ear chopper at 6K WOT.

 

[cdnfthree]

Re: 220 Merc. Laser can't plane out

My boat used to be the same way. Max trim in to a plane or else the boat will porpoise as you already know. AS you are achieving plane the motor needs to be in process of trimming back out. I run mine at about 20 degrees to the transon just the keep the bottom of the boat dry. As long as the motor still gets enough water pumped through it, the steering proplem disappears. It used to try to throw me out of the boat. Now, I wish I'd read my manual sooner.

 

[cdnfthree]

Re: 220 Merc. Laser can't plane out

I've seen the lasers with 220's. It's a wonder that they ever plane out with all of that stern weight. Try trowing some sand bags in the bow of the boat

 

[Silvertip]

Re: 220 Merc. Laser can't plane out

Or add Nauticus "Smart Tabs".

 

[Jamesone]

Re: 220 Merc. Laser can't plane out

I don't remember the rpms at wot, but I believe it is about 4800 (could possibly be 5800 but I just don't remember for sure, but my mechanic did say that the rpm was about right). I think the prop is a 22 pitch 3 blade chopper. I have put new plugs in with no help. I have thought about trying to raise the motor, but have not had a chance to yet. This motor will not even try to rev up with a standard style prop. It just comes up to about 1500 rpms and bogs. with the chopper, I can get some revs then the power starts to come on and it will finally plane - maybe around 10 second or so. Once on plane I can trim up and fly. I do seem to have spark to all cylinders, but if I start pulling plug wires at idle I don't hear a change except on about 2 of the cylinders. I have looked at all of the injector and they are spraying and fuel pressure is okay. I thought my injectors may be dirty, but in my thinking it would not run well on the top either. The boat I have is an old test boat from Mercruiser. They had tested an L-drive system in it, so I had to revamp the transom are to hang this motor so I am not sure about the height. I have gotten it onto plane with 4 people in the boat, but just barely. Once on plane it ran good even with the extra weight. I am open to ideas. I would like to get rid of the boat as I have no need for it, but don't want to sell someone my problems.

 

[Jdeagro]

Re: 220 Merc. Laser can't plane out

Jamesone;<br /><br />It is nice that you are trying to get it set up correctly before you sell it. Your information is a bit loose. You realy need to determine the WOT rpm's, and the WOT speed, and where the antiventilation plate is in relationship to the bottom of the boat. The prop issue sounds as though the regualr prop has too much pitch.<br /><br />Getting on plane may take some time if the boat is excessively stern heavy, but you should be able to do it. For better performance at all levels Smart Tabs or trim tabs in general would be a tremendous help. However, check the other issues first. I do not like to use our Smart Tabs to hide a problem.

 

[Jamesone]

Re: 220 Merc. Laser can't plane out

Where should the antiventilation plate be in relation to the bottom of the boat? My motor sets back a long way from the rear of the boat because the boat used to be an L-drive test boat. When I redid the transom area, I did not extend the bottom of the boat, so the bottom stops, then there is a step up of about 6-8 inches followed by a slightly upward angling flat area of about 18-20 inches, then finally the transom area angles up from here. The motor also hangs on a 10 inch jackplate that is necessary to help clear the stearing cables etc. When you add all of this together, the prop is a long way from the bottom/rear of the boat.