Engine Cooling issue

[riodecolumbia]

So I recently purchased my first boat, a 1991 Regal Valanti 190 with a 4.3 L Mercruiser engine. The motor runs fine, but appears to have some sort of cooling issue. I had the boat in the water recently and it was running good until I saw the temperature gauge rising rapidly. So I shut off the boat, and took it out of the water. I put muffs on the ports on the outdrive of the motor a few days later to see what it would do, and there was no water running through the motor when I checked with the muffs on.
I am very mechanically inclined with cars and thing, but relatively new to the boat scene. So I was wondering if anyone on here could help me with this issue I’m having.

 

[Scott Danforth]

welcome aboard

first, with any new to you boat, assume the prior owner did nothing as far as maintenance

first order of business with your boat

• pull the drive [*=1]do a bellows kit [*=1]check the gimbal bearing [*=1]check the alignment [*=1]check the u-joints
• split the drive and install new raw water pump assembly
• re-install drive
• add gear oil
• change engine oil and filter
• change plugs
• inspect cap/rotor/wires
• re-pack trailer wheel bearings
• inspect trailer winch and rope
• service the trailer brakes.

since you ran it warm without water, you will now need to replace the exhaust flappers and rubber exhaust hoses

 

[BudL1te]

I would venture to say that your impeller needs to be changed. They only last a couple of years if you are careful with them but if it is bad then you will not get the water from the lower unit to the engine whether you use the muffs or in the water.

There are a lot of videos online showing how to replace impellers, it is not hard to do (as long as the bolts cooperate) You can get the kit online pretty cheaply.

 

[BudL1te]

Scott's post is dead on also. Although I would rather someone else did the ujoints/Gimbal/Bellows These require some specialty tools, patience and experience to do without pulling your hair out. There are good videos online that walk you through it though and it is not impossible but just a pain. At a minimum, have them checked so you know where you stand with them and when they would need to be serviced.

Everything else in his list is very important and can save a lot of headaches while you enjoy your time in the water. Wheel bearings should always be maintained and packed yearly. Sucks being on the side of the road on the weekend when parts stores are closed.

I would add to make sure your bilge pump works also. They are pretty cheap online if not.

 

[riodecolumbia]

I would venture to say that your impeller needs to be changed. They only last a couple of years if you are careful with them but if it is bad then you will not get the water from the lower unit to the engine whether you use the muffs or in the water.

There are a lot of videos online showing how to replace impellers, it is not hard to do (as long as the bolts cooperate) You can get the kit online pretty cheaply.

Thank you for the help, I had a feeling it was some sort of pump or impeller possibly in the lower unit but I was not sure. I’ll go ahead and pull the lower unit off and see what it looks like there. Then next I’ll get onto the list Scott posted above, which is very helpful by the way.

 

[Bt Doctur]

Make sure you KNOW how to remove it first

 

[Scott Danforth]

there are vids by achris in the stickies for removing the drive

when in doubt, look at the stickies

remember 90% of youtube content is wrong, or posted by a sweaty-thumbed game-player with no actual training or experience.

 

[achris]

... or posted by a sweaty-thumbed game-player with no actual training or experience.

Talking about me again.

Being 1991, it could be Alpha One or Alpha One Gen II. Need a serial number, and we ask ALL posters to include serial numbers when posting (so we can avoid these discussions )

Scott Danforth mentioned stickies... An invaluable source of all that's good and wise on these forums. You'll find them at the top of each of the forum sub-sections, marked 'Sticky'.... Follow the lead to 'Mercruiser Information', and you'll find out things from how to identify which drive you have, to some of the most involved repair procedures....

Also, as Scott mentioned, there's a LOT of bad and just plain WRONG information out there in youtube-land... Get the factory manual, that will be your 'got to' reference. Then look at some videos, and if they don't jive with the manual, give it a 'thumbs down' and move to the next one.....

As always, here (these forums) are going to be the best source you can find. Many experienced and knowledgeable people with literally hundreds of years of experience to back you up.... If you have any questions, or doubts about information you find elsewhere, you can ask about it here. We're always happy to steering you in the right direction....

And if you have even the remotest doubt or question about a procedure, ask here BEFORE you break something. Here's a great example of 'do first, ask later' :facepalm:....

I pulled my shift cable out to replace it, how do I get the new one in? Well, if he'd asked FIRST, we would have advised him to try a cord to the end of the old cable BEFORE pulling it out. Then he'd have had a way of pulling the new one though and into the same path as the old one.... But he didn't..... So, the only 'stupid question' is the one not asked....

As already stated, but I will again, :welcome: to iboats. We hope your stay will be long and fruitful....

Cheers,

Chris.............
iboats Mod team.