Bought my first boat to cut, gut and rebuild from bow to stern, including engine. Killed my back and suffered the wrath of the fiberglass demons

[alldodge]

Foam doesn't provide increase in buoyancy, the size of the hull does. The foam is used to stiffen the structure and can keep the boat from sinking to the bottom if swamped, but this depends on hull design and amount of foam.

The boats weight limit is there for safety. A overloaded boat can become unstable and be swamped easier. So if you and 2 others will exceed the weight limit, then maybe not a good idea

Asking questions will give you good answers "IF" the owner is honest and does know what they are talking about. You need to know what to look for and how to test to verify, or bring someone with that does know

Many have exceeded the HP limit, but do check with your insurance company before doing. A 85 HP 2-stroke motor will weight less then a 85 HP 4-stroke. In most cases a higher HP 2-stroke will also weight more, so keep this in mind when proceeding with max weight limit

 

[redneck joe]

I have some random questions that I just thought of if you all would be happy to assist with.

1. I am assuming that there is foam in the hull that will need to be removed and replaced. I also assume the foam is there to assist wit stability and buoyancy? If it assists with buoyancy, then theoretically, if there are certain parts of the hull that can have extra foam added to it, would that increase the weight limit? I am a slightly bigger guy and the boat has a 750lb weight limit. 3 grown men could theoretically exceed that limit and I was kind of hoping to have perhaps 4 or 5 people on the boat if possible.

2. I am exploring the option of finding another used but intact and working motor. It seems kind of a pain to find a mechanic around here who is willing to touch the one I have just to clean, bore and reassemble it. I might end up paying the same price for one that is already put together. In searching for a new motor, what are some good questions that I can ask the owner to better help myself come to an educated answer as to whether or not I want to purchase it?

3.The engine max hp limit is 85hp. Can I go larger? Google says any larger risks ripping the transom off the boat. I would like to stick with 85 just because its what I already have, but to be honest, I know next to nothing about boat motors. Will smaller hp reduce the speed/power? Larger increase it? I am not looking for a speed boat, but also not looking for something that can't even reach a kayak's speed LOL, I read that 75-90hp will get me between 25 and 40mph max speed. Is this correct?

1. Weight is inclusive of all gear,coolers, etc. Foam is for keeping boat from sinking in a catastrophic event, nothing to do with everyday use.

2. Pressure test all cylinders. Motor specific numbers posted here to see if good but above all else they all need to be similar psi.

3. You most likely will be replacing all transom wood so if done correctly a slightly larger engine will be fine. Think 327 versus 350 chevy block in a car. Now, you would not want to drop that 350 into a ford fiesta.... Some states and insurance companies will not insure or you can be sued if something bad happens withan oversized motor.

 

[TripleJGraffis]

if you post all here then when complete you stay up late one night copy and paste into a new thread. If a couple posts sneak in whilst doing that you can ask a mod to delete them, of course with a courtesy private message to the person being deleted from the thread. You can also then ask a mod to lock the thread from future posts.

Thank you!

 

[TripleJGraffis]

Foam doesn't provide increase in buoyancy, the size of the hull does. The foam is used to stiffen the structure and can keep the boat from sinking to the bottom if swamped, but this depends on hull design and amount of foam.

The boats weight limit is there for safety. A overloaded boat can become unstable and be swamped easier. So if you and 2 others will exceed the weight limit, then maybe not a good idea

Asking questions will give you good answers "IF" the owner is honest and does know what they are talking about. You need to know what to look for and how to test to verify, or bring someone with that does know

Many have exceeded the HP limit, but do check with your insurance company before doing. A 85 HP 2-stroke motor will weight less then a 85 HP 4-stroke. In most cases a higher HP 2-stroke will also weight more, so keep this in mind when proceeding with max weight limit

What do I need to look for/ask? How do I run tests?

 

[redneck joe]

What do I need to look for/ask? How do I run tests?

Since this is your first boat, find a good mechanic and bring him with you. Ive had over 20 boats and i still dont know much. However if you know motors, then do what you would do for any motor.

 

[TripleJGraffis]

1. Weight is inclusive of all gear,coolers, etc. Foam is for keeping boat from sinking in a catastrophic event, nothing to do with everyday use.

2. Pressure test all cylinders. Motor specific numbers posted here to see if good but above all else they all need to be similar psi.

3. You most likely will be replacing all transom wood so if done correctly a slightly larger engine will be fine. Think 327 versus 350 chevy block in a car. Now, you would not want to drop that 350 into a ford fiesta.... Some states and insurance companies will not insure or you can be sued if something bad happens withan oversized motor.

How do I run a pressure test?

 

[alldodge]

Since this is your first boat, find a good mechanic and bring him with you.

Agree

 

[TripleJGraffis]

Since this is your first boat, find a good mechanic and bring him with you. Ive had over 20 boats and i still dont know much. However if you know motors, then do what you would do for any motor.

Does any motor mechanic know how to do this, or is this specific to boat motor mechanics?

 

[alldodge]

Any can do it
To do a compression test, pull plugs and attach Compression gauge
Open throttle wide open and crank motor over at least 4 times and record reading. Remove gauge and move to next cylinder and repeat until all have been tested

Remove drain plug slightly just enough to see if any water is in the gear lube

Starter should be able to crank the motor over quickly

Start motor and see how it runs on muffs or a tank of water

 

[TripleJGraffis]

Any can do it
To do a compression test, pull plugs and attach Compression gauge
Open throttle wide open and crank motor over at least 4 times and record reading. Remove gauge and move to next cylinder and repeat until all have been tested

Remove drain plug slightly just enough to see if any water is in the gear lube

Starter should be able to crank the motor over quickly

Start motor and see how it runs on muffs or a tank of water

This is valuable information! Thank you!

 

[mickyryan]

When doing pressure test always squirt some lube innthe cylinders like wd40 or even pb blaster , if it hasnt been warmed up best option is warming up first then testing but ill assume thats not a option for you

 

[Lou C]

People do run those old engines basically till it wears out or apart fails that you can’t find for replacement.
If you’re going forward with restoring this boat you will be better off if you view it as a long term project & learning experience. I’ve kind of done that with our boat. Turned out well but at my age can’t do it again. Only option is a good late model (5 years old or less) & a 4 stroke outboard

 

[Scott Danforth]

I have some random questions that I just thought of if you all would be happy to assist with.

1. I am assuming that there is foam in the hull that will need to be removed and replaced. I also assume the foam is there to assist wit stability and buoyancy? If it assists with buoyancy, then theoretically, if there are certain parts of the hull that can have extra foam added to it, would that increase the weight limit?

2. I am exploring the option of finding another used but intact and working motor. It seems kind of a pain to find a mechanic around here who is willing to touch the one I have just to clean, bore and reassemble it

3.The engine max hp limit is 85hp. Can I go larger?

1 your weight limit is based on the boat length and width. The foam is usually structural, and aids in keeping it at the surface when you sink the boat. You can not add weight capacity

2. The cost to rebuild the motor will exceed it's value. Looks for machine shops that specialize in old motors. A good used outboard will be in the $500-1000 range. Remanufacturing your power head will be more than $1500

3. The engine HP limit is based on the length of the boat, width of the transom and the height of the transom. Going larger is not recommended

 

[TripleJGraffis]

When doing pressure test always squirt some lube innthe cylinders like wd40 or even pb blaster , if it hasnt been warmed up best option is warming up first then testing but ill assume thats not a option for you

Is a pressure test and compression test the same thing?

 

[redneck joe]

Yes

 

[TripleJGraffis]

People do run those old engines basically till it wears out or apart fails that you can’t find for replacement.
If you’re going forward with restoring this boat you will be better off if you view it as a long term project & learning experience. I’ve kind of done that with our boat. Turned out well but at my age can’t do it again. Only option is a good late model (5 years old or less) & a 4 stroke outboard

1 your weight limit is based on the boat length and width. The foam is usually structural, and aids in keeping it at the surface when you sink the boat. You can not add weight capacity

2. The cost to rebuild the motor will exceed it's value. Looks for machine shops that specialize in old motors. A good used outboard will be in the $500-1000 range. Remanufacturing your power head will be more than $1500

3. The engine HP limit is based on the length of the boat, width of the transom and the height of the transom. Going larger is not recommended

I agree. I am looking at a 75hp engine on the other side of the state. Gentleman has not spoken with me yet but description says he's aging and just wants to part with it. Allegedly as low hours. I would preferably wait until I can possibly find a good used motor from a shop, but if I can find a good deal on a good old motor, I wouldn't be opposed to looking at it. Thoughts?

 

[TripleJGraffis]

Yes

Yes to what? Compression and pressure tests?

 

[redneck joe]

Yes

 

[alldodge]

Compression and pressure tests

Same test different term used

 

[Lou C]

Whatever you’re looking at if it’s an older motor make sure certain critical parts are available. Like:
Carb rebuild kits
Ignition rebuild or tune up kits
Ignition coil or magneto depending on the style of ignition.

See what engines are available in your area then research parts supply.