Advance problem?

[ottawamerc]

I have a new to me 1981 20' Tempest with a 228 hp and a R model outdrive. It has a stainless 19" pitch prop. It comes out of the hole really poorly and will only get to 3450 rpm. The last owner told me that it worked well before with a skier and went arount 45 mph. He replaced the engine before he put it away for 4 yrs and I bought it.<br />I've been told that the spark advance could be the problem. Ive tested the advance and it is at 8 deg. at idle and does seem to advance but is it far enough?<br />Any ideas

 

[rodbolt]

Re: Advance problem?

hello<br /> 8* at idle is about base timing. total advance must be checked at about 3000 to 3200 RPM. no other way to test it. I would recommend testing it with some one competent at the helm that is NOT a life insureance beneficiary <br /> good luck and keep posting

 

[Don S]

Re: Advance problem?

In order to check how many degrees you have, you will need a timing light that you can adjust the advance on. Sears makes them and they are always on ebay fairly cheap. <br />If you really want to cheap out, you might try putting the 0º mark on the pulley on the 0 mark on the pointer. Then make a mark at the 10º part on the pointer on the pulley. Then move the 10º mark to 0 on the pointer and make another mark at 10 which will actually be 20º<br />Then repeat the process to make a mark for 30º.<br />Then when you run the engine at 3000 rpm, the 30º mark should be real close to the pointer.

 

[Hog Wild]

Re: Advance problem?

You sound like you are really guessing here. Could be anything from carb, throttle adjustment not reaching WOT, ignition system not performing, blocked exhaust, air intake, bad fuel, or perhaps internal engine issues. Sounds like your timing is ok. 8 btdc should be right then mid to upper 20's about 3000 rpms (has to be far off to cause issues). as long as your close to in that range then timing is not the issue. My number one thought though, is the prop. the correct one / original one? Did the motor ever run right? Is the carb. opening up fully, (is the linkage adjusted right). Does the motor appear to run fine but just not have any power? Idle ok? I have to admit though, everything you post here sounds ok. 19" pitch prop. sounds about right.

 

[daveswaves]

Re: Advance problem?

"The last owner told me that it worked well before with a skier and went arount 45 mph. He replaced the engine before he put it away for 4 yrs"<br /><br />It is possible that the advance weights under the distributor plate are rusted closed after 4 years of sitting. Your initial advance is ok but you need the weights to bring in the rest of the advance at speed.<br /><br />Seems strange that if it worked well the last time he used it that he would put a new engine in and then store it.

 

[Don S]

Re: Advance problem?

Don't forget, people selling boats don't always tell the truth about what they are selling. And they probably say that they are selling it in "As is" condition.

 

[fastimz]

Re: Advance problem?

I'm going to agree with Hog Wild. I think you have a problem in another area. I replaced an engine that had been sitting for 8 years and had been partly under water. I used the original distributor with no work done to it, worked fine. I would start with the carb. on the engine end and the prop on the outdrive end

 

[ron7000]

Re: Advance problem?

Originally posted by ottawamerc:<br /> He replaced the engine before he put it away for 4 yrs and I bought it.<br />

My vote is it's all in the carb, especially if it sat for 4 years.<br /><br />a 19" prop on a 20' boat sounds about right. Even if it were pitched too high, you should still see 4000 rpm.

 

[ottawamerc]

Re: Advance problem?

Thanks for the replys.<br />I have rebuilt the carb, checked the lower end so I think its in the timing. Now what about if I replace the distribuor with a GM HE unit, I know it's not a marine unit but would it work?

 

[Don S]

Re: Advance problem?

NO! Not only is it an explosion hazard, and not Coast Guard certified for use in boats, it also has the wrong advance curve. It could actually cause the problem you are trying to cure.<br />Did you test the advance like I discribed earlier? If not, you can do a quick and dirty check by finding the 0 mark on the pulley and measre off about 2" and put a mark. If that line then is somewhere near the 0 mark on the pointer, at 3000 rpm, then the advance is fine.<br />Have you tried trimming the drive out when running? Perhaps the boat is plowing.<br />Have you checked to make sure the carb throttle plate is fully open when the throttle lever is at WOT.<br />Is the prop in good shape. If the blades are bent up and nicked all over, that could sure cause an rpm loss.<br />Then there is a compression check....all you would need is a valve sticking open to cause the problem.<br />Even a vacuum gauge test on the engine. If you have a leak some place in the intake manifold or carb gasket and loose vacuum, you will not get rpms.<br />From your first post, all that you have been worried about is the advance. You do have some but you don't know how much