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1986 Bayliner Overheating

F

flamron

Member
Changed the water tube that go

Changed the water tube that goes to the outdrive that regularly gets corroded and the attached hose. The motor is the 2.1 4 cyl. volvo aq125B. What else can I look for that would cause it to overheat on higher RPM's
 
"Your exhaust manifold could h

"Your exhaust manifold could have the cooling passages corroded and choked with scale. When was the last time you boiled it or replaced it?

Also, the raw water pump impeller could be defective; the raw water strainer coould be plugged-up with debris; or the heat exchanger could be choked. A loose alternator belt can also give you cooling problems.

Another reason for overheating could be engine overload due to having a propeller with too much pitch or diameter. How many engine RPM do you get at WOT?"
 
"i am only getting 4200 rpm at

"i am only getting 4200 rpm at WOT. I am thinking the carb may need rebuilt tho. Strainer is good, I just changed it last week. How hard is the impellar to check/change? Where do I get a new impellar for it? THanks.

ROn"
 
"Your engine should be doing 4

"Your engine should be doing 4700-5000 RPM at WOT. You may want to try a propeller 2"-3" smaller in pitch and see whether or not the engine overheats.

Regarding the impeller, you only have to remove the pump cover and work the impeller out with a couple of screwdrivers. When you install back either the old or a new impeller, make sure the impeller keyway aligns with the key. The Seloc manual describes the procedure in detail."
 
"I took the prop off and it sa

"I took the prop off and it says it is a R219. So I assume it has a 19degree pitch? Does that sound too high for this 4cyl? Also, I was wondering if you knew if an autozone or O'Reileys might have the exhaust manifold gaskets in stock, and if they did, what year and type of volvo would it be?

The thing that bothers me is this: I changed just the connector on Saturday and took the boat out with the original hose on it. The boat still got hot, but it only got to about 210. On Sunday, I put the new hose on (found my socket set). It was a little longer than the original hose, but not by more than a couple inches (if that). I took it out Sunday and it was reaching 225 when I ran it full throttle (still only 4100ish RPMs). I would stop and let it cool down and then I could go for another five-ten minutes before it would overheat again. Thanks for all the help El Pescador, don't know what I would do without you."
 
"Also, what types of props sho

"Also, what types of props should I be looking for that would be compatible with my 270 outdrive? I am not sure what I am looking for when I am searching for them. Thanks again!"
 
"Glad to be of help.

Regard

"Glad to be of help.

Regarding the propeller, there are usually two dimensions stamped on it: diameter and pitch. For example, when you see stamped 14 x 19", that means you have a 14" diameter propeller and 19" pitch. The number R219 may be a factory code, but it does not tell anything about pitch or diameter. Perhaps the pitch and diameter are stamped somewhere in your propeller's hub? Otherwise, you can take it to a propeller shop where they can measure its pitch. The diameter is easy to find: just measure from the center of the propeller shaft nut to the tip of one of the blades, and multiply the result by 2.

Typical propellers for a 4-cyl Volvo (110-140 HP) are 14 x 15", 14 x 17" and 14 x 19" (I have also tried a cupped 15 x 15" prop with very good results).

Here is a link to a document that contains good info about propeller basics:

http://www.miwheel.com/MIWheel/pdf/OBSD04.pdf

The high coolant temperature combined with the low RPM reading could be an indication that the prop you are currently using is too large for your boat. I was wondering if there is in your area either a Volvo Penta dealer or a propeller shop that would lend you a couple of used propellers so that you could test them in your boat in order to determine which one is right for your application.

Regarding exhaust gaskets, any 1980s Volvo 4-cylinder engine has the same exhaust gasket pattern as yours. You should be able to get those gaskets from any autoparts store."
 
"If you have a short shaft, yo

"If you have a short shaft, you can only install short hub propellers; but if you have a long shaft, you can install either short or long hub props. To see the difference, have a look at page 46 (98 of 104) of the document in the link I made in my previous post.
Also, here is a picture with the two most common types of props.
26027.jpg


The one at the left is a long hub and the one at the right is a short hub, but the important thing is that the one at the left has a wider blade and it is engineered for thrust, while the one at the right has a narrower blade and a cup, which makes it more suitable for speed. Which type you use depends of what you are after, and it may take a bit of experimentation to find out which one gives you the best overall performance (top end speed, hole shot, etc)."
 
"I have found a 15x15 on ebay

"I have found a 15x15 on ebay that is 110.00 that will fit. However, it is LH and I do not know if I have a RH or LH prop. Does it make a difference or is that something I can change on the boat? I have also found a RH that is a bit cheaper than the LH. I will wait for your words of wisdom on this purchase El. I really, really appreciate your assistance. If you ever get to NW Arkansas, give me a hollar and I will offer you a beer and a ride in the boat."
 
"Thanks for the offer, Ron. Wi

"Thanks for the offer, Ron. Will keep it in mind.

Now back to the prop, before you buy anything it is very important that you determine first what prop you have installed, because from that info you can determine which size prop you need. Remember that decrease of 2" pitch will give you 300-400 more RPM, so in your case you need a prop with approximately 3" less pitch than what you currently have. Normal places to stamp diameter and pitch are the front of the hub, the back of the hub, and the side of the hub. In any case, if you don't find that info stamped in your prop, I already told you how to measure the diameter, and a prop shop can measure the pitch for you.

Also, keep in mind that most aluminum propellers can have their current pitch increased or decreased about 2" by a prop shop, and this is cheaper than buying a new one.

If there is a Volvo Penta or a propeller shop in your area, you may want to consider asking them to lend you a couple of used props for testing in your boat (most of the times they can be very accommodating, because they expect you will buy the prop if it works for you).

Most of the Volvo packages come with a left-handed propeller, but you can install a right-handed propeller by just changing the shift rod from port to starboard (or viceversa), you should have the instructions on a sticker in the back of the shift cover in the outdrive. The props I showed you in the above pictures are left-handed, as you can see that the helix in the hub goes towards the left (the opposite happens to right-handed propellers)."
 
"Yes, it is right handed. Also

"Yes, it is right handed. Also, your type of propeller should have the pitch and diameter stamped in the front of the hub, as in the picture (sometimes you have to remove some paint to see it). You may want to check this again.

26048.jpg
"
 
"I got the paint off and looke

"I got the paint off and looked really close and all I can say for sure is that it is 14" and either 19 or 17. The 7/9 is too worn to make any real identification. So, would the 14x15 or a 15x15 work most likely, or would it be too much?"
 
"I suppose it could also be th

"I suppose it could also be the R that I am seeing and I can't see any of the pitch number. Go figure, I have a prop that has no ID. Thanks El."
 
"If you have currently install

"If you have currently installed a 14 x 19, then you could try either a 14 x17 or a 14 x 15, or even a 15 x 15 (a 1" increase in diameter roughly absorbs the torque of 2" or 3" of pitch). However, if you have currently installed a 14 x 17, it would make sense to test a 14 x 15, not a 15 x 15."
 
"I pulled the exhaust manifold

"I pulled the exhaust manifold off (quite a task, even though my manual says simply remove these bolts). Anyways, I flow checked the pipe that connects to the bottom of the manifold with my kitchen sink sprayer thingy (good technical term, huh?) and it seemed like it wanted to come out the end before it wanted to travel through the manifold. I took the pipe off (I fortuneatly have another gasket, as that one was toast) and it has some build up, but isn't bad. Does the exhaust manifold require a lot of water pressure to travel through the manifold, or am I plugged up somewhere inside? I have read about boiling these, but am not sure what would be required to do this.

Also, I had to remove the heat exchanger in this process. Is there something I can pour down it to clean it? I don't really want to take it apart just yet, as I want to use the boat tommorrow. The top of the heat exchanger appears to be in really good condition, no muck i.e.

I can see why mechanics want to charge an arm and a leg to do this crap. And I thought my wife's old Cavalier was a PITA to work on, lol.

Thanks El.

Ron"
 
"Upon further inspection, one

"Upon further inspection, one of the holes on the manifold is about half plugged. What can I do to unplug it? Thanks."
 
"Ron, if your manifold is more

"Ron, if your manifold is more than 4-5 years old and it is choked (like yours), I think that your best bet is to replace it. This is the one you need:

http://www.marineengine.com/parts/part_details.php?pnum=SIE18-1930-1&returntopag e=80240783.htm

You can also take your current manifold to a radiator shop for boiling it in acid, but results are not guaranteed. If there is too much internal wastage it can become perforated.

Regarding your heat exchanger, it can also be boiled for cleaning, but results are not guaranteed. When clogged, the best thing to do is to replace the insert."
 
"Well, I really don't want

"Well, I really don't want to spend the money on the exhaust manifold this late in the season. I think I will do that in the spring. Anyways, I "drilled" the hole out that was plugged up with a tiny drill bit and then kept increasing size. I put it back on and took it out yesterday. Temp was a steady 180 degrees. I do agree that I need a new exhaust manifold, but with only about three weeks left in the season, culminated with the fact that I have put about 500 into it right now, and the fact that the boss has said I can't spend any more money on it, I will wait until next season to change it, along with a new impeller. I appreciate all your assistance in my problem fisherman. I will let you know how the prop change does on the RPM's either tommorrow or Weds. I am fairly certain I need to rebuild the carb as well, as I think the accelerator pump is causing me to bog on take off. That can wait until the spring as well though. Is there anything I can spray on the carb to give it a little assistance until next season?

Thanks a MILLION!

Ron"
 
"Hi Ron,

If your carbs are

"Hi Ron,

If your carbs are dirty, sometimes the use of a carb cleaning product may help. However, I think you would be wasting your money at this stage of the game, since you intend to do a carb rebuild anyway. The one thing you may want to check in the meantime is that the accelerator pump spring and linkages are in good condition (you can free them with WD40 if they are seized)."
 
Put new prop on today and took

Put new prop on today and took it out. It maxed out at about 5200 RPM. I may have it bent over the winter by a degree or so to lower the RPM's. Thanks El.
 
"Glad to see that your engine

"Glad to see that your engine is responding well with lower load. One suggestion: if you are going to increase the propeller pitch one or two inches, make sure the propeller blades are cupped; and if they are not, then ask the shop to cup them. A cupped propeller normally makes a significant difference in performance."
 
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