Top Speed in a '89 TS6M

Hey guys,

Just curious to see what my top end should be in my 89 comp? I'm only hitting around 36 to 38 at approx. 3800 RPM right now, which I think it should be higher than that since it is a 3 event boat.

I'm running with an Acme 4 blade right now, 13x12.5 I believe. This prop shouldn't cut back my top end that much. Any other ideas what the issue could be? When I bring the boat out of storage I plan on having a tune up done as well, caps, rotors etc. Could I have a problem with the carb as well?

Cheers,

DZ.

Dinoz,

There are a ton of factors that go into getting a high top end out of your boat. I have the same boat, except mine is 4 years older. When I bought the boat it only went 38. With some modifications it now does 41 in the summer and 43 in the fall water here in WIsconsin.

Your RPMs should be up around 4200. I would check the throttle linkage on the engint at WOT to ensure that the linkage is moving to it's extrematies.

Has the carb ever been rebuilt? If not I would recommend doing so. Make sure the carb air/idle is adjusted after this process along with the timing. I cannot stress the importance of TIMING after a rebuild.

I noticed that my secondary diaphram was shot when I thought everything was fine.

Also the 4 blade prop will knock off some of the top end. A 3 blade 12.5 X 12.5 will give you the best max speed for the boat, however you will sacrifice torque out of the hole with a 3 blade.

If you haven't converted to electronic ignigtion, I would recommend doing so. It helps a lot. I'm pretty sure I still have an extra one. Let me know if you have/haven't converted yours.

Your tune up will also help. Don't forget to gap all of your spark plugs!

Enjoy the off-season!

Thanks for the info!

I haven't had the carb rebuilt, yet. I have heard of the power valve causing some grief as well. Regarding the throttle linkage, how would you check that? Is is ok to rev to motor to WOT in neutral to see the travel length? I do not have an electronic egnition, that was one of the things that I would like to change as well. If you have an extra one, just let me know what you would like for it.

I am not too concern with top end speed, however I woud like to achieve 38 to 40 mph. I am a bigger guy so having the hole shot is important to me as well.

I'm always interesting in seeing other members boats as well, so if you do have any pics of your ride I would love to see them. you can send them to: [email protected]

3 more weeks until the boat show up here in Toronto, can't wait to see all the new rigs!

Cheers,

DZ.

We will get this boat going 38!

To check the throttle you don't need to run the engine. You can do it Right NOw. Get in your boat and remove the engine cover. Place the throttle in the wide open position. Next go back and locate where the throttle attaches to the engine. Try to push the linkage further than the throttle lever has pulled it. If you can push it further you need to adjust it, If not move on.

I would definatly re-build your carb too. You can pick up a kit for a reasonable price and it will only take a few hours. The power valve was fine, despite numerous backfires but I replaced it anyways.

I will check to make sure I still have that electronic ignition kit and give you an estimate (hopefully tomorrow).

Take care,
Tom

I would change the fuel filter/water separator also. If you still have the old style canister filter with the orange top, i'd highly recommend changing the assembly to a new one that has a screw on filter that looks just like an oil filter. Much easier to change.

DKJ

others have given you pretty much the advise I would have - check the vacuum diaphram on the secondaries in addition to the otherthings mentioned. By way of comparison, my '88 runs out at about 43-44mph, basically stock except for a Pertronix ignition.

I had a similar problem and tried the same repairs suggested above. (electronic ignition, carb rebuild) I then decided to "uncork" the supertrapps on the exhaust pipes. In doing this, I discovered a MESS OF DEBRIS clogging them. (rust from the manifolds/pipes, even the remains of the impeller I disintigrated 2 years before) ... I've left them uncorked, and that got me 200 or so more RPM (and a sweet exhaust rumble!!) I then turned my attention to the timing and advanced it fairly heavily, don't remember the exact number, but way more than the 6 degrees printed on the block label, I think it was around 15 or so. Currently I'm getting 4300 RPM and about 43mph, a great idle ... 500 RPM, and decent fuel economy (are any 8's economical???)

In my opinion,

to gain RPM (and top speed accordingly) -- Open up the pipes, and advance the timing.


This is in an 87 Comp TS6M w/ 351W

PoolGuy,

Thanks for the tip. Hoping not to sound like a rookie, what do you mean by the super traps?

DZ.

Supertrapps is a brand name for the style of muffler on my boat ... no "muffler" in the traditional sense, just a series of plates bolted to the end of the exhaust pipe that lets it breathe. The more plates = more air let out. I removed mine completely so it runs just straight pipes, that's when I achieved the biggest increase in RPM. As far as the timing, get a good timing light (and someone who knows how to use one if you don't) and go out and play with it on the water, top speed runs, advancing the timing each run until you find the sweet spot. Unfortunately that will have to wait a few months!!

If you look at the two pipes under the swim platform, and they have a 1/2" bolt in the middle of a stainless steel cap, pull them off to inspect. if full of debris, clean them and replace. alternately, leave them off, I did on mine, sounds great, LOUD, but that's what it's all about!!

Actually, I see you live in Waterloo, I'm actually in Guelph, so if you have any questions, or want me to help you out with your boat, let me know. I'm only 15 mins away. 519-835-POOL

Where do you run around here? Belwood?

Jeff

Cool man that your in Guelph. For most of the season we're up at the cottage in Muskoka, but before we bring it up we're typically at Conestoga Lake. This year however we'll be at Belwood a lot more sinse friends of our have a cottage out there now.

I'll definately give you a buzz when the season starts. If you see a green Comp that will be us. I have my ride posted on this site as well if you want to check it out, it's under "my 89 Comp" I believe.

Mine did the same thing. Ceaning the carb was a huge difference, as well as updating to the new thread on water seperator. I finally put a different cam and heads on it and went to a 13X12.5 3 blade and could pull 44. Also, where you have the wakeplate set can affect up to a mile per hour. Since then I have done some more upgrades and can get over 50 at 4800. If you have any questions et me know.

Jason
87 comp

I have an '88 TS6m Comp that had the supertrapps removed - I was told by a reliable mechanic that it is dangerous to leave those off and operate the boat. The concern is water backing up into the exhaust pipes and into the engine. I noticed that PoolGuy recommended to leave them off (and left his off) - any problems?

rssmithwick, your boat would have to be half sunk before water got into the motor from the exhaust. Just look at how high your risers are at the motor -- that's how far your boat woud have to be under water for it to backflush into the motor. If you're still worried about water getting into you motor buy some of those rubber flappers to give you a free flowing exhaust. If you're in fresh water make sure there aren't any muskrats near by -- they eat rubber like candy and you'll have to be buying new ones every month.

Thanks for the info OUI - I appreciate it! I guess it was just bad information from a not-so-good mechanic!

The flappers DO have a purpose. They are there in case the engine backfires. When it truly backfires, it actually turns the motor in reverse. That CAN suck water right into the cylinders through the riser, manifold, and exhaust valves. When a backfire happens, the suction pulls the flapper up against the exhaust outlet and stops water from coming in

Yall may be talking about something else though.

OUI. LOL, the muskrats used to try and nest up in the exhaust of my folks' 26' Trojan cruiser they had in the early 80's

DKJ

When I went to synthetic oil in my '90, I got 2-300 more RPMs which got me a couple more MPH and sustained speed. I had always consistently hit 40 or 41 unless the water was "unfootable", but with the synthetic lubricants I hit 42 or 43 depending on water. I also used the synthetic tranny fluid. Amsoil is what I use.

I have not seen the stainless caps, mine also has the rubber flappers & I agree completely in regards to leaving them in place. Not only the point about backfiring but consider when your comming down off speed. As you slow down the water behind your boat is moving faster than you are & is going right up the tailpipes... I wouldnt risk it.

Hi there, you mentioned something about converting to electronic ignition. I just bought an '87 ts6m with the PCM Ford 351 motor, do you have any brand or package suggestions for that setup? The motor also has a Holly carb that at this time needs rebuilding as it doesn't run right. I bought from the 2nd owner, and he knows the 1st owner and thinks that the 1st owner replaced the carb to "upgrade" or get more power, which having owned several inboard ski boats I know that won't aid in top speed. Frankly, I think the carb could even be factory stock, BUT, if it were yours, would you invest in changing to a marine EFI conversion, and if so is there a clear choice for that? Or just stick with a carb and rebuild and maintain? Thx much, Michael

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Originally Posted by ATXts6m

Hi there, you mentioned something about converting to electronic ignition. I just bought an '87 ts6m with the PCM Ford 351 motor, do you have any brand or package suggestions for that setup? The motor also has a Holly carb that at this time needs rebuilding as it doesn't run right. I bought from the 2nd owner, and he knows the 1st owner and thinks that the 1st owner replaced the carb to "upgrade" or get more power, which having owned several inboard ski boats I know that won't aid in top speed. Frankly, I think the carb could even be factory stock, BUT, if it were yours, would you invest in changing to a marine EFI conversion, and if so is there a clear choice for that? Or just stick with a carb and rebuild and maintain? Thx much, Michael

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There are several electronic conversions available. Pertronix is one, SKIDIM has 1 that they sell, If I was doing it all over I think I would go with a DUI (Davis Unified Ignition) distributer for simplicity. If you don't know anything about the carb I think your best bet is a new Holley marine carb, best investment I ever made to my boat.