Top Speed in a '89 TS6M

[Dinoz]

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.

[SupraTom]

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!

[Dinoz]

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.

[SupraTom]

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

[DKJBama92Mariah]

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

[washmaster]

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.

[PoolGuy]

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

[Dinoz]

PoolGuy,

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

DZ.

[PoolGuy]

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

[Dinoz]

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.