78 70 HP FRUSTRATION!

[MESS147415]

Hello again you boaters across the pond. Ive just had a week off work with the kids playing with the boat, all is nearly right apart from this continuing prob. Engine is on a 14 foot simms ski boat. Starts fine, runs for five mins on fast idle while i clear the marina, give it some throttle and it will rev up onto pane and run at high revs fine. Prob starts if the engine is then allowed to stop or idle for more than about a minute. Engine will run at fast idle but stalls if given full gas, running for a couple of mins at fast idle again and full throttle can then be used. Priming bulb is always hard, but i did find that a very quick blip on the choke will overcome the prob indicating to me a fuel prob? Any ideas please? I have stripped and re built the carbs - one suggestion has been bigger idle jets. thanks steve

 

[steviecops]

Re: 78 70 HP FRUSTRATION!

Is it overheating?

 

[MESS147415]

Re: 78 70 HP FRUSTRATION!

Hi stevie, i dont think its overheating - there is always a good flow thro the pee hole althogh this does steam after a good run. How can i check if im overheating? steve

 

[steviecops]

Re: 78 70 HP FRUSTRATION!

Sorry for the delay Steve, been working!<br /><br />I would agree about the fuel problem, but you say you've just stripped, cleaned and rebuilt the carbs. Did you use new kits?, and did you really give all the jets and pasages a good clean and blow through with compressed air? Did you set the float levels correctly?<br /><br />If the primer bulb is staying hard, I wouldn't imagine it would be your fuel pump or an air leak anywhere, but it would still be worth checking out.<br /><br />The fact that all seems O.K until you let the engine idle after a hard run leads me to believe that it may be an overheating problem, but I'm no expert. Maybe some of the others could jump in if they think I'm way off. Also, I wouldn't have thought that steam or steaming water through the peehole is good news.<br /><br />You should be able to hold your fingers on top of the cylinder head for a couple of seconds before having to pull them away. If you can't hold them there without burning yourself, you're running too hot. Another way to check is with a heat sensor, you need to check the manual but I would think up to 145-150 degrees would be O.K.<br /><br />The good flow of water through the peehole doesn't mean that you're not overheating. It doesn't even mean that you've got a flow of water through the block and head. <br /><br />Let us know how you get on, and take it from there.<br /><br />Good luck<br />Steve